Implement NIP-21: nostr: URI scheme with full support for note, nprofile, nevent, and naddr URIs including TLV encoding/decoding and comprehensive test suite

README.md

@@ -26,11 +26,11 @@ A C library for NOSTR protocol implementation. Work in progress.
 - [ ] [NIP-14](nips/14.md) - Subject tag in text events
 - [ ] [NIP-15](nips/15.md) - Nostr Marketplace (for resilient marketplaces)
 - [ ] [NIP-16](nips/16.md) - Event Treatment
-- [ ] [NIP-17](nips/17.md) - Private Direct Messages
+- [x] [NIP-17](nips/17.md) - Private Direct Messages
 - [ ] [NIP-18](nips/18.md) - Reposts
 - [x] [NIP-19](nips/19.md) - bech32-encoded entities
 - [ ] [NIP-20](nips/20.md) - Command Results
-- [ ] [NIP-21](nips/21.md) - `nostr:` URI scheme
+- [x] [NIP-21](nips/21.md) - `nostr:` URI scheme
 - [ ] [NIP-22](nips/22.md) - Event `created_at` Limits
 - [ ] [NIP-23](nips/23.md) - Long-form Content
 - [ ] [NIP-24](nips/24.md) - Extra metadata fields and tags
@@ -50,7 +50,7 @@ A C library for NOSTR protocol implementation. Work in progress.
 - [ ] [NIP-38](nips/38.md) - User Statuses
 - [ ] [NIP-39](nips/39.md) - External Identities in Profiles
 - [ ] [NIP-40](nips/40.md) - Expiration Timestamp
-- [ ] [NIP-42](nips/42.md) - Authentication of clients to relays
+- [x] [NIP-42](nips/42.md) - Authentication of clients to relays
 - [x] [NIP-44](nips/44.md) - Versioned Encryption
 - [ ] [NIP-45](nips/45.md) - Counting results
 - [ ] [NIP-46](nips/46.md) - Nostr Connect
@@ -66,7 +66,7 @@ A C library for NOSTR protocol implementation. Work in progress.
 - [ ] [NIP-56](nips/56.md) - Reporting
 - [ ] [NIP-57](nips/57.md) - Lightning Zaps
 - [ ] [NIP-58](nips/58.md) - Badges
-- [ ] [NIP-59](nips/59.md) - Gift Wrap
+- [x] [NIP-59](nips/59.md) - Gift Wrap
 - [ ] [NIP-60](nips/60.md) - Cashu Wallet
 - [ ] [NIP-61](nips/61.md) - Nutzaps
 - [ ] [NIP-62](nips/62.md) - Log events
@@ -96,7 +96,7 @@ A C library for NOSTR protocol implementation. Work in progress.
 
 **Legend:** ✅ Fully Implemented | ⚠️ Partial Implementation | ❌ Not Implemented
 
-**Implementation Summary:** 8 of 96+ NIPs fully implemented (8.3%)
+**Implementation Summary:** 12 of 96+ NIPs fully implemented (12.5%)
 
 
 ## 📦 Quick Start
@@ -523,7 +523,7 @@ The library uses automatic semantic versioning based on Git tags. Each build inc
 - `v0.2.x` - Current development releases with enhanced NIP support
 - `v0.1.x` - Initial development releases
 - Focus on core protocol implementation and OpenSSL-based crypto
-- Full NIP-01, NIP-04, NIP-05, NIP-06, NIP-11, NIP-13, NIP-19, NIP-44 support
+- Full NIP-01, NIP-04, NIP-05, NIP-06, NIP-11, NIP-13, NIP-17, NIP-19, NIP-42, NIP-44, NIP-59 support
 
 ## 🐛 Troubleshooting
 

VERSION

@@ -1 +1 @@
-0.4.4
+0.4.5

build.sh

@@ -142,6 +142,7 @@ if [ "$HELP" = true ]; then
     echo "  013 - Proof of Work"
     echo "  017 - Private Direct Messages"
     echo "  019 - Bech32 encoding (nsec/npub)"
+    echo "  021 - nostr: URI scheme"
     echo "  042 - Authentication of clients to relays"
     echo "  044 - Encryption (modern)"
     echo "  059 - Gift Wrap"
@@ -230,7 +231,7 @@ fi
 
 # If building tests or examples, include all NIPs to ensure compatibility
 if ([ "$BUILD_TESTS" = true ] || [ "$BUILD_EXAMPLES" = true ]) && [ -z "$FORCE_NIPS" ]; then
-    NEEDED_NIPS="001 004 005 006 011 013 017 019 042 044 059"
+    NEEDED_NIPS="001 004 005 006 011 013 017 019 021 042 044 059"
     print_info "Building tests/examples - including all available NIPs for compatibility"
 fi
 
@@ -518,6 +519,7 @@ for nip in $NEEDED_NIPS; do
             013) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-013(PoW)" ;;
             017) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-017(DMs)" ;;
             019) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-019(Bech32)" ;;
+            021) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-021(URI)" ;;
             042) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-042(Auth)" ;;
             044) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-044(Encrypt)" ;;
             059) NIP_DESCRIPTIONS="$NIP_DESCRIPTIONS NIP-059(Gift-Wrap)" ;;

nostr_core/core_relay_pool.c

@@ -777,9 +777,6 @@ static void process_relay_message(nostr_relay_pool_t* pool, relay_connection_t*
     
     relay->stats.last_event_time = time(NULL);
 
-    // Debug: Print all message types received
-    printf("📨 DEBUG: Received %s message from %s\n", msg_type, relay->url);
-
     if (strcmp(msg_type, "EVENT") == 0) {
         // Handle EVENT message: ["EVENT", subscription_id, event]
         if (cJSON_IsArray(parsed) && cJSON_GetArraySize(parsed) >= 3) {

nostr_core/nip021.c

@@ -0,0 +1,855 @@
+/*
+ * NOSTR Core Library - NIP-021: nostr: URI scheme
+ */
+
+#include "nip021.h"
+#include "nip019.h"  // For existing bech32 functions
+#include "utils.h"
+#include "nostr_common.h"  // For error codes
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include "../cjson/cJSON.h"
+
+// Forward declarations for internal parsing functions
+static int parse_nprofile_data(const uint8_t* data, size_t data_len, nostr_nprofile_t* nprofile);
+static int parse_nevent_data(const uint8_t* data, size_t data_len, nostr_nevent_t* nevent);
+static int parse_naddr_data(const uint8_t* data, size_t data_len, nostr_naddr_t* naddr);
+
+// Bech32 constants and functions (copied from nip019.c for internal use)
+static const char bech32_charset[] = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
+static const int8_t bech32_charset_rev[128] = {
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    15, -1, 10, 17, 21, 20, 26, 30,  7,  5, -1, -1, -1, -1, -1, -1,
+    -1, 29, -1, 24, 13, 25,  9,  8, 23, -1, 18, 22, 31, 27, 19, -1,
+    1,  0,  3, 16, 11, 28, 12, 14,  6,  4,  2, -1, -1, -1, -1, -1,
+    -1, 29, -1, 24, 13, 25,  9,  8, 23, -1, 18, 22, 31, 27, 19, -1,
+    1,  0,  3, 16, 11, 28, 12, 14,  6,  4,  2, -1, -1, -1, -1, -1
+};
+
+static uint32_t bech32_polymod_step(uint32_t pre) {
+    uint8_t b = pre >> 25;
+    return ((pre & 0x1FFFFFF) << 5) ^
+           (-((b >> 0) & 1) & 0x3b6a57b2UL) ^
+           (-((b >> 1) & 1) & 0x26508e6dUL) ^
+           (-((b >> 2) & 1) & 0x1ea119faUL) ^
+           (-((b >> 3) & 1) & 0x3d4233ddUL) ^
+           (-((b >> 4) & 1) & 0x2a1462b3UL);
+}
+
+static int convert_bits(uint8_t *out, size_t *outlen, int outbits, const uint8_t *in, size_t inlen, int inbits, int pad) {
+    uint32_t val = 0;
+    int bits = 0;
+    uint32_t maxv = (((uint32_t)1) << outbits) - 1;
+    *outlen = 0;
+    while (inlen--) {
+        val = (val << inbits) | *(in++);
+        bits += inbits;
+        while (bits >= outbits) {
+            bits -= outbits;
+            out[(*outlen)++] = (val >> bits) & maxv;
+        }
+    }
+    if (pad) {
+        if (bits) {
+            out[(*outlen)++] = (val << (outbits - bits)) & maxv;
+        }
+    } else if (((val << (outbits - bits)) & maxv) || bits >= inbits) {
+        return 0;
+    }
+    return 1;
+}
+
+static int bech32_encode(char *output, const char *hrp, const uint8_t *data, size_t data_len) {
+    uint32_t chk = 1;
+    size_t i, hrp_len = strlen(hrp);
+
+    for (i = 0; i < hrp_len; ++i) {
+        int ch = hrp[i];
+        if (ch < 33 || ch > 126) return 0;
+        if (ch >= 'A' && ch <= 'Z') return 0;
+        chk = bech32_polymod_step(chk) ^ (ch >> 5);
+    }
+
+    chk = bech32_polymod_step(chk);
+    for (i = 0; i < hrp_len; ++i) {
+        chk = bech32_polymod_step(chk) ^ (hrp[i] & 0x1f);
+        *(output++) = hrp[i];
+    }
+
+    *(output++) = '1';
+    for (i = 0; i < data_len; ++i) {
+        if (*data >> 5) return 0;
+        chk = bech32_polymod_step(chk) ^ (*data);
+        *(output++) = bech32_charset[*(data++)];
+    }
+
+    for (i = 0; i < 6; ++i) {
+        chk = bech32_polymod_step(chk);
+    }
+
+    chk ^= 1;
+    for (i = 0; i < 6; ++i) {
+        *(output++) = bech32_charset[(chk >> ((5 - i) * 5)) & 0x1f];
+    }
+
+    *output = 0;
+    return 1;
+}
+
+static int bech32_decode(const char* input, const char* hrp, unsigned char* data, size_t* data_len) {
+    if (!input || !hrp || !data || !data_len) {
+        return 0;
+    }
+
+    size_t input_len = strlen(input);
+    size_t hrp_len = strlen(hrp);
+
+    if (input_len < hrp_len + 7) return 0;
+    if (strncmp(input, hrp, hrp_len) != 0) return 0;
+    if (input[hrp_len] != '1') return 0;
+
+    const char* data_part = input + hrp_len + 1;
+    size_t data_part_len = input_len - hrp_len - 1;
+
+    uint8_t values[256];
+    for (size_t i = 0; i < data_part_len; i++) {
+        unsigned char c = (unsigned char)data_part[i];
+        if (c >= 128) return 0;
+        int8_t val = bech32_charset_rev[c];
+        if (val == -1) return 0;
+        values[i] = (uint8_t)val;
+    }
+
+    if (data_part_len < 6) return 0;
+
+    uint32_t chk = 1;
+    for (size_t i = 0; i < hrp_len; i++) {
+        chk = bech32_polymod_step(chk) ^ (hrp[i] >> 5);
+    }
+    chk = bech32_polymod_step(chk);
+    for (size_t i = 0; i < hrp_len; i++) {
+        chk = bech32_polymod_step(chk) ^ (hrp[i] & 0x1f);
+    }
+    for (size_t i = 0; i < data_part_len; i++) {
+        chk = bech32_polymod_step(chk) ^ values[i];
+    }
+
+    if (chk != 1) return 0;
+
+    size_t payload_len = data_part_len - 6;
+    size_t decoded_len;
+    if (!convert_bits(data, &decoded_len, 8, values, payload_len, 5, 0)) {
+        return 0;
+    }
+
+    *data_len = decoded_len;
+    return 1;
+}
+
+// TLV (Type-Length-Value) constants for structured data
+#define TLV_SPECIAL 0
+#define TLV_RELAY 1
+#define TLV_AUTHOR 2
+#define TLV_KIND 3
+#define TLV_CREATED_AT 4
+#define TLV_IDENTIFIER 5
+
+// Forward declarations for internal functions
+static int tlv_encode(const uint8_t* data, size_t data_len, uint8_t type, uint8_t** output, size_t* output_len);
+static int encode_structured_bech32(const char* hrp, const uint8_t* data, size_t data_len, char* output, size_t output_size);
+static int decode_structured_bech32(const char* input, const char* expected_hrp, uint8_t** data, size_t* data_len);
+
+// Utility function to duplicate string array (removed - not used)
+
+// Free string array
+static void free_string_array(char** array, int count) {
+    if (!array) return;
+    for (int i = 0; i < count; i++) {
+        free(array[i]);
+    }
+    free(array);
+}
+
+// TLV encoding: Type (1 byte) + Length (1 byte) + Value
+static int tlv_encode(const uint8_t* data, size_t data_len, uint8_t type, uint8_t** output, size_t* output_len) {
+    if (data_len > 255) return 0; // Length must fit in 1 byte
+
+    *output_len = 2 + data_len;
+    *output = malloc(*output_len);
+    if (!*output) return 0;
+
+    (*output)[0] = type;
+    (*output)[1] = (uint8_t)data_len;
+    memcpy(*output + 2, data, data_len);
+    return 1;
+}
+
+// TLV decoding (removed - not used)
+
+// Encode structured data to bech32
+static int encode_structured_bech32(const char* hrp, const uint8_t* data, size_t data_len, char* output, size_t output_size) {
+    // For simple cases like note (32 bytes), use the existing key encoding
+    if (strcmp(hrp, "note") == 0 && data_len == 32) {
+        return nostr_key_to_bech32(data, "note", output);
+    }
+
+    uint8_t conv[256];
+    size_t conv_len;
+
+    if (!convert_bits(conv, &conv_len, 5, data, data_len, 8, 1)) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    if (!bech32_encode(output, hrp, conv, conv_len)) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    if (strlen(output) >= output_size) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+// Decode structured bech32 data
+static int decode_structured_bech32(const char* input, const char* expected_hrp, uint8_t** data, size_t* data_len) {
+    // bech32_decode already converts from 5-bit to 8-bit internally
+    *data = malloc(256);  // Max size
+    if (!*data) return NOSTR_ERROR_MEMORY_FAILED;
+
+    if (!bech32_decode(input, expected_hrp, *data, data_len)) {
+        free(*data);
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+// Detect URI type from string
+nostr_uri_type_t nostr_detect_uri_type(const char* uri) {
+    if (!uri) return NOSTR_URI_INVALID;
+
+    // Check for nostr: prefix
+    if (strncmp(uri, "nostr:", 6) != 0) {
+        return NOSTR_URI_INVALID;
+    }
+
+    const char* bech32_part = uri + 6;
+
+    // Check prefixes
+    if (strncmp(bech32_part, "npub1", 5) == 0) return NOSTR_URI_NPUB;
+    if (strncmp(bech32_part, "nsec1", 5) == 0) return NOSTR_URI_NSEC;
+    if (strncmp(bech32_part, "note1", 5) == 0) return NOSTR_URI_NOTE;
+    if (strncmp(bech32_part, "nprofile1", 9) == 0) return NOSTR_URI_NPROFILE;
+    if (strncmp(bech32_part, "nevent1", 7) == 0) return NOSTR_URI_NEVENT;
+    if (strncmp(bech32_part, "naddr1", 6) == 0) return NOSTR_URI_NADDR;
+
+    return NOSTR_URI_INVALID;
+}
+
+// Free URI result resources
+void nostr_uri_result_free(nostr_uri_result_t* result) {
+    if (!result) return;
+
+    switch (result->type) {
+        case NOSTR_URI_NPROFILE:
+            free_string_array(result->data.nprofile.relays, result->data.nprofile.relay_count);
+            break;
+        case NOSTR_URI_NEVENT:
+            free_string_array(result->data.nevent.relays, result->data.nevent.relay_count);
+            free(result->data.nevent.author);
+            free(result->data.nevent.kind);
+            free(result->data.nevent.created_at);
+            break;
+        case NOSTR_URI_NADDR:
+            free(result->data.naddr.identifier);
+            free_string_array(result->data.naddr.relays, result->data.naddr.relay_count);
+            break;
+        default:
+            break;
+    }
+}
+
+// Main URI parsing function
+int nostr_parse_uri(const char* uri, nostr_uri_result_t* result) {
+    if (!uri || !result) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    memset(result, 0, sizeof(nostr_uri_result_t));
+
+    nostr_uri_type_t type = nostr_detect_uri_type(uri);
+    if (type == NOSTR_URI_INVALID) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    const char* bech32_part = uri + 6; // Skip "nostr:"
+    result->type = type;
+
+    int ret;
+    switch (type) {
+        case NOSTR_URI_NPUB: {
+            ret = nostr_decode_npub(bech32_part, result->data.pubkey);
+            break;
+        }
+        case NOSTR_URI_NSEC: {
+            ret = nostr_decode_nsec(bech32_part, result->data.privkey);
+            break;
+        }
+        case NOSTR_URI_NOTE: {
+            // Note is similar to npub but with "note" prefix
+            uint8_t* decoded;
+            size_t decoded_len;
+            ret = decode_structured_bech32(bech32_part, "note", &decoded, &decoded_len);
+            if (ret == NOSTR_SUCCESS) {
+                if (decoded_len == 32) {
+                    memcpy(result->data.event_id, decoded, 32);
+                } else {
+                    ret = NOSTR_ERROR_INVALID_INPUT;
+                }
+                free(decoded);
+            }
+            break;
+        }
+        case NOSTR_URI_NPROFILE: {
+            uint8_t* decoded;
+            size_t decoded_len;
+            ret = decode_structured_bech32(bech32_part, "nprofile", &decoded, &decoded_len);
+            if (ret == NOSTR_SUCCESS) {
+                ret = parse_nprofile_data(decoded, decoded_len, &result->data.nprofile);
+                free(decoded);
+            }
+            break;
+        }
+        case NOSTR_URI_NEVENT: {
+            uint8_t* decoded;
+            size_t decoded_len;
+            ret = decode_structured_bech32(bech32_part, "nevent", &decoded, &decoded_len);
+            if (ret == NOSTR_SUCCESS) {
+                ret = parse_nevent_data(decoded, decoded_len, &result->data.nevent);
+                free(decoded);
+            }
+            break;
+        }
+        case NOSTR_URI_NADDR: {
+            uint8_t* decoded;
+            size_t decoded_len;
+            ret = decode_structured_bech32(bech32_part, "naddr", &decoded, &decoded_len);
+            if (ret == NOSTR_SUCCESS) {
+                ret = parse_naddr_data(decoded, decoded_len, &result->data.naddr);
+                free(decoded);
+            }
+            break;
+        }
+        default:
+            ret = NOSTR_ERROR_INVALID_INPUT;
+            break;
+    }
+
+    if (ret != NOSTR_SUCCESS) {
+        nostr_uri_result_free(result);
+        memset(result, 0, sizeof(nostr_uri_result_t));
+    }
+
+    return ret;
+}
+
+// Parse nprofile structured data
+static int parse_nprofile_data(const uint8_t* data, size_t data_len, nostr_nprofile_t* nprofile) {
+    size_t offset = 0;
+
+    while (offset < data_len) {
+        if (offset + 2 > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        uint8_t type = data[offset];
+        uint8_t length = data[offset + 1];
+        offset += 2;
+
+        if (offset + length > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        switch (type) {
+            case TLV_SPECIAL: // pubkey
+                if (length != 32) return NOSTR_ERROR_INVALID_INPUT;
+                memcpy(nprofile->pubkey, data + offset, 32);
+                break;
+            case TLV_RELAY: // relay URL
+                {
+                    char* relay = malloc(length + 1);
+                    if (!relay) return NOSTR_ERROR_MEMORY_FAILED;
+                    memcpy(relay, data + offset, length);
+                    relay[length] = '\0';
+
+                    char** new_relays = realloc(nprofile->relays, (nprofile->relay_count + 1) * sizeof(char*));
+                    if (!new_relays) {
+                        free(relay);
+                        return NOSTR_ERROR_MEMORY_FAILED;
+                    }
+                    nprofile->relays = new_relays;
+                    nprofile->relays[nprofile->relay_count++] = relay;
+                }
+                break;
+            default:
+                // Ignore unknown types
+                break;
+        }
+        offset += length;
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+// Parse nevent structured data
+static int parse_nevent_data(const uint8_t* data, size_t data_len, nostr_nevent_t* nevent) {
+    size_t offset = 0;
+
+    while (offset < data_len) {
+        if (offset + 2 > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        uint8_t type = data[offset];
+        uint8_t length = data[offset + 1];
+        offset += 2;
+
+        if (offset + length > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        switch (type) {
+            case TLV_SPECIAL: // event ID
+                if (length != 32) return NOSTR_ERROR_INVALID_INPUT;
+                memcpy(nevent->event_id, data + offset, 32);
+                break;
+            case TLV_RELAY: // relay URL
+                {
+                    char* relay = malloc(length + 1);
+                    if (!relay) return NOSTR_ERROR_MEMORY_FAILED;
+                    memcpy(relay, data + offset, length);
+                    relay[length] = '\0';
+
+                    char** new_relays = realloc(nevent->relays, (nevent->relay_count + 1) * sizeof(char*));
+                    if (!new_relays) {
+                        free(relay);
+                        return NOSTR_ERROR_MEMORY_FAILED;
+                    }
+                    nevent->relays = new_relays;
+                    nevent->relays[nevent->relay_count++] = relay;
+                }
+                break;
+            case TLV_AUTHOR: // author pubkey
+                if (length != 32) return NOSTR_ERROR_INVALID_INPUT;
+                nevent->author = malloc(32);
+                if (!nevent->author) return NOSTR_ERROR_MEMORY_FAILED;
+                memcpy(nevent->author, data + offset, 32);
+                break;
+            case TLV_KIND: // kind
+                if (length != 4) return NOSTR_ERROR_INVALID_INPUT;
+                nevent->kind = malloc(sizeof(int));
+                if (!nevent->kind) return NOSTR_ERROR_MEMORY_FAILED;
+                *nevent->kind = (data[offset] << 24) | (data[offset+1] << 16) | (data[offset+2] << 8) | data[offset+3];
+                break;
+            case TLV_CREATED_AT: // created_at
+                if (length != 8) return NOSTR_ERROR_INVALID_INPUT;
+                nevent->created_at = malloc(sizeof(time_t));
+                if (!nevent->created_at) return NOSTR_ERROR_MEMORY_FAILED;
+                *nevent->created_at = ((time_t)data[offset] << 56) | ((time_t)data[offset+1] << 48) |
+                                     ((time_t)data[offset+2] << 40) | ((time_t)data[offset+3] << 32) |
+                                     ((time_t)data[offset+4] << 24) | ((time_t)data[offset+5] << 16) |
+                                     ((time_t)data[offset+6] << 8) | (time_t)data[offset+7];
+                break;
+            default:
+                // Ignore unknown types
+                break;
+        }
+        offset += length;
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+// Parse naddr structured data
+static int parse_naddr_data(const uint8_t* data, size_t data_len, nostr_naddr_t* naddr) {
+    size_t offset = 0;
+
+    while (offset < data_len) {
+        if (offset + 2 > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        uint8_t type = data[offset];
+        uint8_t length = data[offset + 1];
+        offset += 2;
+
+        if (offset + length > data_len) return NOSTR_ERROR_INVALID_INPUT;
+
+        switch (type) {
+            case TLV_IDENTIFIER: // identifier
+                naddr->identifier = malloc(length + 1);
+                if (!naddr->identifier) return NOSTR_ERROR_MEMORY_FAILED;
+                memcpy(naddr->identifier, data + offset, length);
+                naddr->identifier[length] = '\0';
+                break;
+            case TLV_SPECIAL: // pubkey
+                if (length != 32) return NOSTR_ERROR_INVALID_INPUT;
+                memcpy(naddr->pubkey, data + offset, 32);
+                break;
+            case TLV_KIND: // kind
+                if (length != 4) return NOSTR_ERROR_INVALID_INPUT;
+                naddr->kind = (data[offset] << 24) | (data[offset+1] << 16) | (data[offset+2] << 8) | data[offset+3];
+                break;
+            case TLV_RELAY: // relay URL
+                {
+                    char* relay = malloc(length + 1);
+                    if (!relay) return NOSTR_ERROR_MEMORY_FAILED;
+                    memcpy(relay, data + offset, length);
+                    relay[length] = '\0';
+
+                    char** new_relays = realloc(naddr->relays, (naddr->relay_count + 1) * sizeof(char*));
+                    if (!new_relays) {
+                        free(relay);
+                        return NOSTR_ERROR_MEMORY_FAILED;
+                    }
+                    naddr->relays = new_relays;
+                    naddr->relays[naddr->relay_count++] = relay;
+                }
+                break;
+            default:
+                // Ignore unknown types
+                break;
+        }
+        offset += length;
+    }
+
+    return NOSTR_SUCCESS;
+}
+
+
+// URI construction functions
+
+int nostr_build_uri_npub(const unsigned char* pubkey, char* output, size_t output_size) {
+    if (!pubkey || !output || output_size < 70) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    char bech32[100];
+    int ret = nostr_key_to_bech32(pubkey, "npub", bech32);
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    size_t len = strlen(bech32);
+    if (len + 7 >= output_size) return NOSTR_ERROR_INVALID_INPUT;
+
+    strcpy(output, "nostr:");
+    strcpy(output + 6, bech32);
+    return NOSTR_SUCCESS;
+}
+
+int nostr_build_uri_nsec(const unsigned char* privkey, char* output, size_t output_size) {
+    if (!privkey || !output || output_size < 70) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    char bech32[100];
+    int ret = nostr_key_to_bech32(privkey, "nsec", bech32);
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    size_t len = strlen(bech32);
+    if (len + 7 >= output_size) return NOSTR_ERROR_INVALID_INPUT;
+
+    strcpy(output, "nostr:");
+    strcpy(output + 6, bech32);
+    return NOSTR_SUCCESS;
+}
+
+// Helper to build URI with prefix
+static int build_uri_with_prefix(const char* bech32, char* output, size_t output_size) {
+    size_t len = strlen(bech32);
+    if (len + 7 >= output_size) return NOSTR_ERROR_INVALID_INPUT;
+
+    strcpy(output, "nostr:");
+    strcpy(output + 6, bech32);
+    return NOSTR_SUCCESS;
+}
+
+int nostr_build_uri_note(const unsigned char* event_id, char* output, size_t output_size) {
+    if (!event_id || !output || output_size < 70) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    char bech32[100];
+    int ret = encode_structured_bech32("note", event_id, 32, bech32, sizeof(bech32));
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    return build_uri_with_prefix(bech32, output, output_size);
+}
+
+int nostr_build_uri_nprofile(const unsigned char* pubkey, const char** relays, int relay_count,
+                            char* output, size_t output_size) {
+    if (!pubkey || !output) return NOSTR_ERROR_INVALID_INPUT;
+
+    // Build TLV data
+    uint8_t* data = NULL;
+    size_t data_len = 0;
+
+    // Add pubkey (special)
+    uint8_t* pubkey_tlv;
+    size_t pubkey_tlv_len;
+    if (!tlv_encode(pubkey, 32, TLV_SPECIAL, &pubkey_tlv, &pubkey_tlv_len)) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    data = realloc(data, data_len + pubkey_tlv_len);
+    if (!data) {
+        free(pubkey_tlv);
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+    memcpy(data + data_len, pubkey_tlv, pubkey_tlv_len);
+    data_len += pubkey_tlv_len;
+    free(pubkey_tlv);
+
+    // Add relays
+    for (int i = 0; i < relay_count; i++) {
+        size_t relay_len = strlen(relays[i]);
+        uint8_t* relay_tlv;
+        size_t relay_tlv_len;
+        if (!tlv_encode((uint8_t*)relays[i], relay_len, TLV_RELAY, &relay_tlv, &relay_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + relay_tlv_len);
+        if (!data) {
+            free(relay_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, relay_tlv, relay_tlv_len);
+        data_len += relay_tlv_len;
+        free(relay_tlv);
+    }
+
+    // Encode to bech32
+    char bech32[500];
+    int ret = encode_structured_bech32("nprofile", data, data_len, bech32, sizeof(bech32));
+    free(data);
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    return build_uri_with_prefix(bech32, output, output_size);
+}
+
+int nostr_build_uri_nevent(const unsigned char* event_id, const char** relays, int relay_count,
+                          const unsigned char* author, int kind, time_t created_at,
+                          char* output, size_t output_size) {
+    if (!event_id || !output) return NOSTR_ERROR_INVALID_INPUT;
+
+    // Build TLV data
+    uint8_t* data = NULL;
+    size_t data_len = 0;
+
+    // Add event_id (special)
+    uint8_t* event_tlv;
+    size_t event_tlv_len;
+    if (!tlv_encode(event_id, 32, TLV_SPECIAL, &event_tlv, &event_tlv_len)) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    data = realloc(data, data_len + event_tlv_len);
+    if (!data) {
+        free(event_tlv);
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+    memcpy(data + data_len, event_tlv, event_tlv_len);
+    data_len += event_tlv_len;
+    free(event_tlv);
+
+    // Add relays
+    for (int i = 0; i < relay_count; i++) {
+        size_t relay_len = strlen(relays[i]);
+        uint8_t* relay_tlv;
+        size_t relay_tlv_len;
+        if (!tlv_encode((uint8_t*)relays[i], relay_len, TLV_RELAY, &relay_tlv, &relay_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + relay_tlv_len);
+        if (!data) {
+            free(relay_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, relay_tlv, relay_tlv_len);
+        data_len += relay_tlv_len;
+        free(relay_tlv);
+    }
+
+    // Add author if provided
+    if (author) {
+        uint8_t* author_tlv;
+        size_t author_tlv_len;
+        if (!tlv_encode(author, 32, TLV_AUTHOR, &author_tlv, &author_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + author_tlv_len);
+        if (!data) {
+            free(author_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, author_tlv, author_tlv_len);
+        data_len += author_tlv_len;
+        free(author_tlv);
+    }
+
+    // Add kind if provided
+    if (kind >= 0) {
+        uint8_t kind_bytes[4];
+        kind_bytes[0] = (kind >> 24) & 0xFF;
+        kind_bytes[1] = (kind >> 16) & 0xFF;
+        kind_bytes[2] = (kind >> 8) & 0xFF;
+        kind_bytes[3] = kind & 0xFF;
+
+        uint8_t* kind_tlv;
+        size_t kind_tlv_len;
+        if (!tlv_encode(kind_bytes, 4, TLV_KIND, &kind_tlv, &kind_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + kind_tlv_len);
+        if (!data) {
+            free(kind_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, kind_tlv, kind_tlv_len);
+        data_len += kind_tlv_len;
+        free(kind_tlv);
+    }
+
+    // Add created_at if provided
+    if (created_at > 0) {
+        uint8_t time_bytes[8];
+        time_bytes[0] = (created_at >> 56) & 0xFF;
+        time_bytes[1] = (created_at >> 48) & 0xFF;
+        time_bytes[2] = (created_at >> 40) & 0xFF;
+        time_bytes[3] = (created_at >> 32) & 0xFF;
+        time_bytes[4] = (created_at >> 24) & 0xFF;
+        time_bytes[5] = (created_at >> 16) & 0xFF;
+        time_bytes[6] = (created_at >> 8) & 0xFF;
+        time_bytes[7] = created_at & 0xFF;
+
+        uint8_t* time_tlv;
+        size_t time_tlv_len;
+        if (!tlv_encode(time_bytes, 8, TLV_CREATED_AT, &time_tlv, &time_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + time_tlv_len);
+        if (!data) {
+            free(time_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, time_tlv, time_tlv_len);
+        data_len += time_tlv_len;
+        free(time_tlv);
+    }
+
+    // Encode to bech32
+    char bech32[1000];
+    int ret = encode_structured_bech32("nevent", data, data_len, bech32, sizeof(bech32));
+    free(data);
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    return build_uri_with_prefix(bech32, output, output_size);
+}
+
+int nostr_build_uri_naddr(const char* identifier, const unsigned char* pubkey, int kind,
+                         const char** relays, int relay_count, char* output, size_t output_size) {
+    if (!identifier || !pubkey || !output) return NOSTR_ERROR_INVALID_INPUT;
+
+    // Build TLV data
+    uint8_t* data = NULL;
+    size_t data_len = 0;
+
+    // Add identifier
+    size_t id_len = strlen(identifier);
+    uint8_t* id_tlv;
+    size_t id_tlv_len;
+    if (!tlv_encode((uint8_t*)identifier, id_len, TLV_IDENTIFIER, &id_tlv, &id_tlv_len)) {
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    data = realloc(data, data_len + id_tlv_len);
+    if (!data) {
+        free(id_tlv);
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+    memcpy(data + data_len, id_tlv, id_tlv_len);
+    data_len += id_tlv_len;
+    free(id_tlv);
+
+    // Add pubkey (special)
+    uint8_t* pubkey_tlv;
+    size_t pubkey_tlv_len;
+    if (!tlv_encode(pubkey, 32, TLV_SPECIAL, &pubkey_tlv, &pubkey_tlv_len)) {
+        free(data);
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    data = realloc(data, data_len + pubkey_tlv_len);
+    if (!data) {
+        free(pubkey_tlv);
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+    memcpy(data + data_len, pubkey_tlv, pubkey_tlv_len);
+    data_len += pubkey_tlv_len;
+    free(pubkey_tlv);
+
+    // Add kind
+    uint8_t kind_bytes[4];
+    kind_bytes[0] = (kind >> 24) & 0xFF;
+    kind_bytes[1] = (kind >> 16) & 0xFF;
+    kind_bytes[2] = (kind >> 8) & 0xFF;
+    kind_bytes[3] = kind & 0xFF;
+
+    uint8_t* kind_tlv;
+    size_t kind_tlv_len;
+    if (!tlv_encode(kind_bytes, 4, TLV_KIND, &kind_tlv, &kind_tlv_len)) {
+        free(data);
+        return NOSTR_ERROR_INVALID_INPUT;
+    }
+
+    data = realloc(data, data_len + kind_tlv_len);
+    if (!data) {
+        free(kind_tlv);
+        return NOSTR_ERROR_MEMORY_FAILED;
+    }
+    memcpy(data + data_len, kind_tlv, kind_tlv_len);
+    data_len += kind_tlv_len;
+    free(kind_tlv);
+
+    // Add relays
+    for (int i = 0; i < relay_count; i++) {
+        size_t relay_len = strlen(relays[i]);
+        uint8_t* relay_tlv;
+        size_t relay_tlv_len;
+        if (!tlv_encode((uint8_t*)relays[i], relay_len, TLV_RELAY, &relay_tlv, &relay_tlv_len)) {
+            free(data);
+            return NOSTR_ERROR_INVALID_INPUT;
+        }
+
+        data = realloc(data, data_len + relay_tlv_len);
+        if (!data) {
+            free(relay_tlv);
+            return NOSTR_ERROR_MEMORY_FAILED;
+        }
+        memcpy(data + data_len, relay_tlv, relay_tlv_len);
+        data_len += relay_tlv_len;
+        free(relay_tlv);
+    }
+
+    // Encode to bech32
+    char bech32[1000];
+    int ret = encode_structured_bech32("naddr", data, data_len, bech32, sizeof(bech32));
+    free(data);
+    if (ret != NOSTR_SUCCESS) return ret;
+
+    return build_uri_with_prefix(bech32, output, output_size);
+}

nostr_core/nip021.h

@@ -0,0 +1,81 @@
+/*
+ * NOSTR Core Library - NIP-021: nostr: URI scheme
+ */
+
+#ifndef NIP021_H
+#define NIP021_H
+
+#include <stdint.h>
+#include <time.h>
+#include "nip001.h"
+
+// URI type enumeration
+typedef enum {
+    NOSTR_URI_NPUB,      // Simple 32-byte pubkey
+    NOSTR_URI_NSEC,      // Simple 32-byte privkey
+    NOSTR_URI_NOTE,      // Simple 32-byte event ID
+    NOSTR_URI_NPROFILE,  // Structured: pubkey + relays
+    NOSTR_URI_NEVENT,    // Structured: event ID + relays + metadata
+    NOSTR_URI_NADDR,     // Structured: address + relays + metadata
+    NOSTR_URI_INVALID
+} nostr_uri_type_t;
+
+// Structured data types for complex URIs
+typedef struct {
+    unsigned char pubkey[32];
+    char** relays;
+    int relay_count;
+} nostr_nprofile_t;
+
+typedef struct {
+    unsigned char event_id[32];
+    char** relays;
+    int relay_count;
+    unsigned char* author;     // Optional, 32 bytes if present
+    int* kind;                 // Optional
+    time_t* created_at;        // Optional
+} nostr_nevent_t;
+
+typedef struct {
+    char* identifier;
+    unsigned char pubkey[32];
+    int kind;
+    char** relays;
+    int relay_count;
+} nostr_naddr_t;
+
+// Unified URI result structure
+typedef struct {
+    nostr_uri_type_t type;
+    union {
+        unsigned char pubkey[32];      // For NPUB
+        unsigned char privkey[32];     // For NSEC
+        unsigned char event_id[32];    // For NOTE
+        nostr_nprofile_t nprofile;      // For NPROFILE
+        nostr_nevent_t nevent;         // For NEVENT
+        nostr_naddr_t naddr;           // For NADDR
+    } data;
+} nostr_uri_result_t;
+
+// Function declarations
+
+// Main parsing function - unified entry point
+int nostr_parse_uri(const char* uri, nostr_uri_result_t* result);
+
+// URI construction functions
+int nostr_build_uri_npub(const unsigned char* pubkey, char* output, size_t output_size);
+int nostr_build_uri_nsec(const unsigned char* privkey, char* output, size_t output_size);
+int nostr_build_uri_note(const unsigned char* event_id, char* output, size_t output_size);
+int nostr_build_uri_nprofile(const unsigned char* pubkey, const char** relays, int relay_count,
+                            char* output, size_t output_size);
+int nostr_build_uri_nevent(const unsigned char* event_id, const char** relays, int relay_count,
+                          const unsigned char* author, int kind, time_t created_at,
+                          char* output, size_t output_size);
+int nostr_build_uri_naddr(const char* identifier, const unsigned char* pubkey, int kind,
+                         const char** relays, int relay_count, char* output, size_t output_size);
+
+// Utility functions
+void nostr_uri_result_free(nostr_uri_result_t* result);
+nostr_uri_type_t nostr_detect_uri_type(const char* uri);
+
+#endif // NIP021_H

nostr_core/nostr_core.h

@@ -2,10 +2,10 @@
 #define NOSTR_CORE_H
 
 // Version information (auto-updated by increment_and_push.sh)
-#define VERSION "v0.4.4"
+#define VERSION "v0.4.5"
 #define VERSION_MAJOR 0
 #define VERSION_MINOR 4
-#define VERSION_PATCH 4
+#define VERSION_PATCH 5
 
 /*
  * NOSTR Core Library - Complete API Reference
@@ -177,6 +177,7 @@ extern "C" {
 #include "nip013.h"  // Proof of Work
 #include "nip017.h"  // Private Direct Messages
 #include "nip019.h"  // Bech32 encoding (nsec/npub)
+#include "nip021.h"  // nostr: URI scheme
 #include "nip042.h"  // Authentication of clients to relays
 #include "nip044.h"  // Encryption (modern)
 #include "nip059.h"  // Gift Wrap

tests/nip21_test.c

@@ -0,0 +1,373 @@
+/*
+ * NIP-21 URI Scheme Test Suite
+ * Tests nostr: URI parsing and construction functionality
+ * Following TESTS POLICY: Shows expected vs actual values
+ */
+
+#define _GNU_SOURCE  // For strdup on Linux
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "../nostr_core/nip021.h"
+#include "../nostr_core/nostr_common.h"
+#include "../nostr_core/utils.h"
+
+// Ensure strdup is declared
+#ifndef strdup
+extern char *strdup(const char *s);
+#endif
+
+// Test counter for tracking progress
+static int test_count = 0;
+static int passed_tests = 0;
+
+void print_test_header(const char* test_name) {
+    test_count++;
+    printf("\n=== TEST %d: %s ===\n", test_count, test_name);
+}
+
+void print_test_result(int passed, const char* test_name) {
+    if (passed) {
+        passed_tests++;
+        printf("✅ PASS: %s\n", test_name);
+    } else {
+        printf("❌ FAIL: %s\n", test_name);
+    }
+}
+
+// Test 1: Parse note URI
+int test_parse_note_uri(void) {
+    print_test_header("Parse note: URI");
+
+    // First build a valid note URI, then parse it
+    unsigned char event_id[32];
+    nostr_hex_to_bytes("f1e582c90f071c0110cc5bcac2dcc6d8c32250e3cc26fcbe93470d918f2ffaf0", event_id, 32);
+
+    char built_uri[200];
+    int build_result = nostr_build_uri_note(event_id, built_uri, sizeof(built_uri));
+    if (build_result != NOSTR_SUCCESS) {
+        printf("Failed to build URI for testing: %d (%s)\n", build_result, nostr_strerror(build_result));
+        return 0;
+    }
+
+    printf("Input URI: %s\n", built_uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(built_uri, &result);
+
+    printf("Expected: NOSTR_SUCCESS (0)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    if (parse_result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Expected type: NOSTR_URI_NOTE\n");
+    printf("Actual type: %d\n", result.type);
+
+    if (result.type != NOSTR_URI_NOTE) {
+        return 0;
+    }
+
+    printf("Expected event ID to be set\n");
+    printf("Event ID present: %s\n", result.data.event_id[0] ? "yes" : "no");
+
+    // Verify the parsed event ID matches the original
+    int event_id_match = (memcmp(result.data.event_id, event_id, 32) == 0);
+    printf("Event ID matches original: %s\n", event_id_match ? "yes" : "no");
+
+    return (result.type == NOSTR_URI_NOTE && event_id_match);
+}
+
+// Test 2: Parse nprofile URI
+int test_parse_nprofile_uri(void) {
+    print_test_header("Parse nprofile: URI");
+
+    // First build a valid nprofile URI, then parse it
+    unsigned char pubkey[32];
+    nostr_hex_to_bytes("aa4fc8665f5696e33db7e1a572e3b0f5b3d615837b0f362dcb1c8068b098c7b4", pubkey, 32);
+    const char* relays[] = {"wss://relay.example.com"};
+
+    char built_uri[300];
+    int build_result = nostr_build_uri_nprofile(pubkey, relays, 1, built_uri, sizeof(built_uri));
+    if (build_result != NOSTR_SUCCESS) {
+        printf("Failed to build URI for testing: %d (%s)\n", build_result, nostr_strerror(build_result));
+        return 0;
+    }
+
+    printf("Input URI: %s\n", built_uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(built_uri, &result);
+
+    printf("Expected: NOSTR_SUCCESS (0)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    if (parse_result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Expected type: NOSTR_URI_NPROFILE\n");
+    printf("Actual type: %d\n", result.type);
+
+    if (result.type != NOSTR_URI_NPROFILE) {
+        return 0;
+    }
+
+    // Verify the parsed pubkey matches the original
+    int pubkey_match = (memcmp(result.data.nprofile.pubkey, pubkey, 32) == 0);
+    printf("Pubkey matches original: %s\n", pubkey_match ? "yes" : "no");
+
+    // Verify relay count
+    printf("Expected relay count: 1\n");
+    printf("Actual relay count: %d\n", result.data.nprofile.relay_count);
+
+    return (result.type == NOSTR_URI_NPROFILE && pubkey_match && result.data.nprofile.relay_count == 1);
+}
+
+// Test 3: Parse nevent URI
+int test_parse_nevent_uri(void) {
+    print_test_header("Parse nevent: URI");
+
+    // First build a valid nevent URI, then parse it
+    unsigned char event_id[32];
+    nostr_hex_to_bytes("f1e582c90f071c0110cc5bcac2dcc6d8c32250e3cc26fcbe93470d918f2ffaf0", event_id, 32);
+    const char* relays[] = {"wss://relay.example.com"};
+
+    char built_uri[400];
+    int build_result = nostr_build_uri_nevent(event_id, relays, 1, NULL, 1, 1234567890, built_uri, sizeof(built_uri));
+    if (build_result != NOSTR_SUCCESS) {
+        printf("Failed to build URI for testing: %d (%s)\n", build_result, nostr_strerror(build_result));
+        return 0;
+    }
+
+    printf("Input URI: %s\n", built_uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(built_uri, &result);
+
+    printf("Expected: NOSTR_SUCCESS (0)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    if (parse_result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Expected type: NOSTR_URI_NEVENT\n");
+    printf("Actual type: %d\n", result.type);
+
+    if (result.type != NOSTR_URI_NEVENT) {
+        return 0;
+    }
+
+    // Verify the parsed event ID matches the original
+    int event_id_match = (memcmp(result.data.nevent.event_id, event_id, 32) == 0);
+    printf("Event ID matches original: %s\n", event_id_match ? "yes" : "no");
+
+    // Verify kind
+    printf("Expected kind: 1\n");
+    printf("Actual kind: %d\n", result.data.nevent.kind ? *result.data.nevent.kind : -1);
+
+    // Verify relay count
+    printf("Expected relay count: 1\n");
+    printf("Actual relay count: %d\n", result.data.nevent.relay_count);
+
+    return (result.type == NOSTR_URI_NEVENT && event_id_match && result.data.nevent.relay_count == 1);
+}
+
+// Test 4: Parse naddr URI
+int test_parse_naddr_uri(void) {
+    print_test_header("Parse naddr: URI");
+
+    // First build a valid naddr URI, then parse it
+    const char* identifier = "draft";
+    unsigned char pubkey[32];
+    nostr_hex_to_bytes("aa4fc8665f5696e33db7e1a572e3b0f5b3d615837b0f362dcb1c8068b098c7b4", pubkey, 32);
+    const char* relays[] = {"wss://relay.example.com"};
+
+    char built_uri[400];
+    int build_result = nostr_build_uri_naddr(identifier, pubkey, 30023, relays, 1, built_uri, sizeof(built_uri));
+    if (build_result != NOSTR_SUCCESS) {
+        printf("Failed to build URI for testing: %d (%s)\n", build_result, nostr_strerror(build_result));
+        return 0;
+    }
+
+    printf("Input URI: %s\n", built_uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(built_uri, &result);
+
+    printf("Expected: NOSTR_SUCCESS (0)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    if (parse_result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Expected type: NOSTR_URI_NADDR\n");
+    printf("Actual type: %d\n", result.type);
+
+    if (result.type != NOSTR_URI_NADDR) {
+        return 0;
+    }
+
+    // Verify the parsed identifier matches the original
+    int identifier_match = (strcmp(result.data.naddr.identifier, identifier) == 0);
+    printf("Identifier matches original: %s\n", identifier_match ? "yes" : "no");
+
+    // Verify kind
+    printf("Expected kind: 30023\n");
+    printf("Actual kind: %d\n", result.data.naddr.kind);
+
+    // Verify relay count
+    printf("Expected relay count: 1\n");
+    printf("Actual relay count: %d\n", result.data.naddr.relay_count);
+
+    return (result.type == NOSTR_URI_NADDR && identifier_match && result.data.naddr.relay_count == 1);
+}
+
+// Test 5: Invalid URI (wrong prefix)
+int test_invalid_uri_prefix(void) {
+    print_test_header("Invalid URI - Wrong Prefix");
+
+    const char* uri = "bitcoin:note1example";
+    printf("Input URI: %s\n", uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(uri, &result);
+
+    printf("Expected: NOSTR_ERROR_INVALID_INPUT (-1)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    return (parse_result == NOSTR_ERROR_INVALID_INPUT);
+}
+
+// Test 6: Invalid URI (missing colon)
+int test_invalid_uri_no_colon(void) {
+    print_test_header("Invalid URI - No Colon");
+
+    const char* uri = "nostrnote1example";
+    printf("Input URI: %s\n", uri);
+
+    nostr_uri_result_t result;
+    int parse_result = nostr_parse_uri(uri, &result);
+
+    printf("Expected: NOSTR_ERROR_INVALID_INPUT (-1)\n");
+    printf("Actual: %d (%s)\n", parse_result, nostr_strerror(parse_result));
+
+    return (parse_result == NOSTR_ERROR_INVALID_INPUT);
+}
+
+// Test 7: Build note URI
+int test_build_note_uri(void) {
+    print_test_header("Build note: URI");
+
+    unsigned char event_id[32];
+    nostr_hex_to_bytes("f1e582c90f071c0110cc5bcac2dcc6d8c32250e3cc26fcbe93470d918f2ffaf0", event_id, 32);
+    printf("Input event ID: f1e582c90f071c0110cc5bcac2dcc6d8c32250e3cc26fcbe93470d918f2ffaf0\n");
+
+    char uri[200];
+    int result = nostr_build_uri_note(event_id, uri, sizeof(uri));
+    printf("Build result: %d (%s)\n", result, nostr_strerror(result));
+
+    if (result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Built URI: %s\n", uri);
+    int success = (strncmp(uri, "nostr:note1", 11) == 0);
+    printf("Expected: URI starts with 'nostr:note1'\n");
+    printf("Actual: %s\n", success ? "yes" : "no");
+
+    return success;
+}
+
+// Test 8: Build nprofile URI
+int test_build_nprofile_uri(void) {
+    print_test_header("Build nprofile: URI");
+
+    unsigned char pubkey[32];
+    nostr_hex_to_bytes("aa4fc8665f5696e33db7e1a572e3b0f5b3d615837b0f362dcb1c8068b098c7b4", pubkey, 32);
+    const char* relays[] = {"wss://relay.example.com", "wss://relay2.example.com"};
+    printf("Input pubkey: aa4fc8665f5696e33db7e1a572e3b0f5b3d615837b0f362dcb1c8068b098c7b4\n");
+
+    char uri[300];
+    int result = nostr_build_uri_nprofile(pubkey, relays, 2, uri, sizeof(uri));
+    printf("Build result: %d (%s)\n", result, nostr_strerror(result));
+
+    if (result != NOSTR_SUCCESS) {
+        return 0;
+    }
+
+    printf("Built URI: %s\n", uri);
+    int success = (strncmp(uri, "nostr:nprofile1", 14) == 0);
+    printf("Expected: URI starts with 'nostr:nprofile1'\n");
+    printf("Actual: %s\n", success ? "yes" : "no");
+
+    return success;
+}
+
+int main(void) {
+    printf("=== NIP-21 URI Scheme Test Suite ===\n");
+    printf("Following TESTS POLICY: Shows expected vs actual values\n");
+
+    // Initialize crypto library
+    if (nostr_init() != NOSTR_SUCCESS) {
+        printf("❌ Failed to initialize nostr library\n");
+        return 1;
+    }
+
+    int all_passed = 1;
+    int test_result;
+
+    // Valid URI parsing tests
+    test_result = test_parse_note_uri();
+    print_test_result(test_result, "Parse note: URI");
+    if (!test_result) all_passed = 0;
+
+    test_result = test_parse_nprofile_uri();
+    print_test_result(test_result, "Parse nprofile: URI");
+    if (!test_result) all_passed = 0;
+
+    test_result = test_parse_nevent_uri();
+    print_test_result(test_result, "Parse nevent: URI");
+    if (!test_result) all_passed = 0;
+
+    test_result = test_parse_naddr_uri();
+    print_test_result(test_result, "Parse naddr: URI");
+    if (!test_result) all_passed = 0;
+
+    // Invalid URI tests
+    test_result = test_invalid_uri_prefix();
+    print_test_result(test_result, "Invalid URI - Wrong Prefix");
+    if (!test_result) all_passed = 0;
+
+    test_result = test_invalid_uri_no_colon();
+    print_test_result(test_result, "Invalid URI - No Colon");
+    if (!test_result) all_passed = 0;
+
+    // URI building tests
+    test_result = test_build_note_uri();
+    print_test_result(test_result, "Build note: URI");
+    if (!test_result) all_passed = 0;
+
+    test_result = test_build_nprofile_uri();
+    print_test_result(test_result, "Build nprofile: URI");
+    if (!test_result) all_passed = 0;
+
+    // Summary
+    printf("\n=== TEST SUMMARY ===\n");
+    printf("Total tests: %d\n", test_count);
+    printf("Passed: %d\n", passed_tests);
+    printf("Failed: %d\n", test_count - passed_tests);
+
+    if (all_passed) {
+        printf("🎉 ALL TESTS PASSED! NIP-21 URI scheme implementation is working correctly.\n");
+    } else {
+        printf("❌ SOME TESTS FAILED. Please review the output above.\n");
+    }
+
+    nostr_cleanup();
+    return all_passed ? 0 : 1;
+}

tests/websocket_debug.c

@@ -18,7 +18,7 @@
 int main(int argc, char* argv[]) {
     if (argc < 2) {
         fprintf(stderr, "Usage: %s <relay_url> [event_id]\n", argv[0]);
-        fprintf(stderr, "Example: %s wss://relay.laantungir.net 06cdf2cdd095ddb1ebe15d5b3c736b27a34de2683e847b871fe37d86ac998772\n");
+        fprintf(stderr, "Example: websocket_debug wss://relay.laantungir.net 06cdf2cdd095ddb1ebe15d5b3c736b27a34de2683e847b871fe37d86ac998772\n");
         return 1;
     }