Add POST method support and handle HTTP body parsing

This update introduces support for the POST method and improves HTTP body extraction in request parsing. It adds a new method to get the Content-Length from headers, ensuring the body is correctly extracted and stored. Additionally, it integrates these changes with new tests to validate the functionality.

Took 1 hour 47 minutes

src/tiny_http/tiny_http_server_lib.c

@@ -8,6 +8,26 @@
 #include <stdlib.h>
 #include <string.h>
 
+/**
+ *
+ * @param headers http_headers from which we've to get the Content-Length
+ * @param num_headers number of headers
+ * @return the value of `Content-Length` header or error (negative)
+ * @retval > 0 is the actual value
+ * @retval -1 headers is NULL
+ * @retval -2 the `Content-Length` header is not found
+ */
+ssize_t get_body_size_from_header(const http_header *const *const headers, const size_t num_headers) {
+    if (headers == NULL) return -1;
+    for (size_t i = 0; i < num_headers; i++) {
+        if (headers[i] == NULL) continue;
+        if (strncmp(headers[i]->name, "Content-Length", 15) == 0) {
+            return strtol(headers[i]->value, nullptr, 10);
+        }
+    }
+    return -2;
+}
+
 http_request *parse_http_request(const uint8_t *const http_packet, const size_t http_packet_len) {
     http_request *request = calloc(1, sizeof(http_request));
     if (http_packet != nullptr && http_packet_len <= 5) {
@@ -21,6 +41,10 @@ http_request *parse_http_request(const uint8_t *const http_packet, const size_t
         ptr += 4; // "GET " - 4
         start_uri = 4;
         request->method = GET;
+    } else if (strncmp((char *) http_packet, "POST", 4) == 0) {
+        ptr += 5; // "POST" - 5
+        start_uri = 5;
+        request->method = POST;
     } else {
         fprintf(stderr, "right now, only HTTP GET is supported");
         fflush(stderr);
@@ -74,7 +98,9 @@ http_request *parse_http_request(const uint8_t *const http_packet, const size_t
 
     ptr += 2; // '\r\n'
     for (size_t i = 0; ptr < http_packet_len; i++) {
-        if (ptr + 2 >= http_packet_len) {
+        if ((ptr >= http_packet_len || ptr + 1 >= http_packet_len)
+            || (http_packet[ptr] == '\r'
+                && http_packet[ptr + 1] == '\n')) {
             break;
         }
         http_header *header = calloc(1, sizeof(http_header));
@@ -110,10 +136,18 @@ http_request *parse_http_request(const uint8_t *const http_packet, const size_t
             }
         }
         header->value = strndup((char *) http_packet + ptr - header_value_len, header_value_len);
-        if (request->headers == NULL) {
-            request->headers = calloc(1, sizeof(http_header*));
+        if (request->headers == nullptr) {
+            request->headers = calloc(1, sizeof(http_header *));
         } else {
-            const http_header **new_headers = realloc(request->headers, sizeof(http_header*) * (i + 1));
+            http_header **new_headers = realloc(request->headers, sizeof(http_header *) * (i + 1));
+            if (new_headers == nullptr) {
+                fprintf(stderr, "cannot allocate memory for new headers");
+                fflush(stderr);
+                free(request->url);
+                free(request);
+                free(header);
+                return nullptr;
+            }
             request->headers = new_headers;
         }
         request->headers[i] = header;
@@ -123,8 +157,13 @@ http_request *parse_http_request(const uint8_t *const http_packet, const size_t
 
     ptr += 2;
     if (ptr < http_packet_len) {
-        request->body_len = http_packet_len - ptr;
-        request->body = (uint8_t*) strndup((char *) http_packet + ptr, request->body_len);
+        const ssize_t body_len_from_header = get_body_size_from_header(request->headers, request->headers_cnt);
+        if (body_len_from_header > 0) {
+            request->body_len = body_len_from_header;
+        } else {
+            request->body_len = http_packet_len - ptr;
+        }
+        request->body = (uint8_t *) strndup((char *) http_packet + ptr, request->body_len);
     }
 
     return request;

src/tiny_http/tiny_http_server_lib.h

@@ -13,6 +13,7 @@ typedef enum http_version {
 
 typedef enum http_method {
     GET = 1,
+    POST = 2,
 } http_method;
 
 typedef struct http_header {

test/assert_tiny_http_server_lib.c

@@ -2,33 +2,75 @@
 // Created by Samuel Vishesh Paul on 28/10/24.
 //
 
+#define DEBUG 1
+
 #include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 
 #include "../src/tiny_http/tiny_http_server_lib.h"
 
-int main() {
+void test_request_parse_get_root_curl(void) {
     // ReSharper disable once CppVariableCanBeMadeConstexpr
-    const uint8_t request[] = "GET / HTTP/1.0\r\nHost: localhost:8085\r\nUser-Agent: curl/8.7.1\r\nAccept: */*\r\n\r\n";
-    const http_request* http_req = parse_http_request(request, strlen((char *)request));
+    const uint8_t request[] = "GET / HTTP/1.0\r\n"
+            "Host: localhost:8085\r\n"
+            "User-Agent: curl/8.7.1\r\n"
+            "Accept: */*\r\n"
+            "\r\n";
+    const http_request *http_req = parse_http_request(request, strlen((char *) request));
     assert(http_req != nullptr);
     assert(http_req->method == GET);
     assert(http_req->version == HTTP_1_0);
     assert(strncmp(http_req->url, "/", 1) == 0);
     assert(http_req->headers_cnt == 3);
-    printf("Header 1: '%s': '%s'\n", http_req->headers[0]->name, http_req->headers[0]->value);
     assert(strncmp(http_req->headers[0]->name , "Host", 255) == 0);
     assert(strncmp(http_req->headers[0]->value, "localhost:8085", 255) == 0);
-    printf("Header 2: '%s': '%s'\n", http_req->headers[1]->name, http_req->headers[1]->value);
     assert(strncmp(http_req->headers[1]->name, "User-Agent", 255) == 0);
     assert(strncmp(http_req->headers[1]->value, "curl/8.7.1", 255) == 0);
-    printf("Header 3: '%s': '%s'\n", http_req->headers[2]->name, http_req->headers[2]->value);
     assert(strncmp(http_req->headers[2]->name, "Accept", 255) == 0);
     assert(strncmp(http_req->headers[2]->value, "*/*", 255) == 0);
     assert(http_req->body == nullptr);
     assert(http_req->body_len == 0);
+}
+
+void test_request_post_root_curl(void) {
+    // ReSharper disable once CppVariableCanBeMadeConstexpr
+    const uint8_t request[] = "POST /one/two/three HTTP/1.0\r\n"
+            "Content-Type: application/json\r\n"
+            "User-Agent: PostmanRuntime/7.42.0\r\n"
+            "Accept: */*\r\n"
+            "Host: localhost:8085\r\n"
+            "Accept-Encoding: gzip, deflate, br\r\n"
+            "Content-Length: 68\r\n"
+            "\r\n"
+            "{\n    \"key1\": \"value1\",\n    \"key2\": \"value2\",\n    \"key3\": \"value3\"\n}";
+    const http_request *http_req = parse_http_request(request, strlen((char *) request));
+    assert(http_req != nullptr);
+    assert(http_req->method == POST);
+    assert(http_req->version == HTTP_1_0);
+    assert(strncmp(http_req->url, "/one/two/three", 255) == 0);
+    assert(strncmp(http_req->headers[0]->name, "Content-Type", 255) == 0);
+    assert(strncmp(http_req->headers[0]->value, "application/json", 255) == 0);
+    assert(strncmp(http_req->headers[1]->name, "User-Agent", 255) == 0);
+    assert(strncmp(http_req->headers[1]->value, "PostmanRuntime/7.42.0", 255) == 0);
+    assert(strncmp(http_req->headers[2]->name, "Accept", 255) == 0);
+    assert(strncmp(http_req->headers[2]->value, "*/*", 255) == 0);
+    assert(strncmp(http_req->headers[3]->name, "Host", 255) == 0);
+    assert(strncmp(http_req->headers[3]->value, "localhost:8085", 255) == 0);
+    assert(strncmp(http_req->headers[4]->name, "Accept-Encoding", 255) == 0);
+    assert(strncmp(http_req->headers[4]->value, "gzip, deflate, br", 255) == 0);
+    assert(strncmp(http_req->headers[5]->name, "Content-Length", 255) == 0);
+    assert(strncmp(http_req->headers[5]->value, "68", 255) == 0);
+    assert(http_req->body_len == 68);
+    assert(
+        strncmp((char *) http_req->body,
+            "{\n    \"key1\": \"value1\",\n    \"key2\": \"value2\",\n    \"key3\": \"value3\"\n}", 68) == 0);
+}
+
+int main() {
+    test_request_parse_get_root_curl();
+    test_request_post_root_curl();
 
     return EXIT_SUCCESS;
 }