feat(transport_ws): add header callback hook

Move to a line-by-line header parser.
Support a callback hook for each header-line.
Migrate "Location" and "Sec-WebSocket-Accept" parsing.

Part of https://github.com/espressif/esp-protocols/issues/715

components/tcp_transport/include/esp_transport_ws.h

@@ -29,6 +29,8 @@ typedef enum ws_transport_opcodes {
                                           * from the API esp_transport_ws_get_read_opcode() */
 } ws_transport_opcodes_t;
 
+typedef void (*ws_header_hook)(void * userp, const char * line, int line_len);
+
 /**
  * WS transport configuration structure
  */
@@ -37,6 +39,8 @@ typedef struct {
     const char *sub_protocol;               /*!< WS subprotocol */
     const char *user_agent;                 /*!< WS user agent */
     const char *headers;                    /*!< WS additional headers */
+    ws_header_hook header_hook;             /*!< WS received header */
+    void *header_userp;                     /*!< WS received header user-pointer */
     const char *auth;                       /*!< HTTP authorization header */
     char *response_headers;                 /*!< The buffer to copy the http response header */
     size_t response_headers_len;            /*!< The length of the http response header */
@@ -99,6 +103,31 @@ esp_err_t esp_transport_ws_set_user_agent(esp_transport_handle_t t, const char *
  */
 esp_err_t esp_transport_ws_set_headers(esp_transport_handle_t t, const char *headers);
 
+/**
+ * @brief               Set websocket header callback
+ *
+ * @param t             websocket transport handle
+ * @param hook          call function on header received. NULL to disable.
+ *
+ * @return
+ *      - ESP_OK on success
+ *      - One of the error codes
+ */
+esp_err_t esp_transport_ws_set_header_hook(esp_transport_handle_t t, ws_header_hook hook);
+
+
+/**
+ * @brief               Set websocket header callback user-pointer
+ *
+ * @param t             websocket transport handle
+ * @param userp         caller-controlled argument to ws_header_hook
+ *
+ * @return
+ *      - ESP_OK on success
+ *      - One of the error codes
+ */
+esp_err_t esp_transport_ws_set_header_userp(esp_transport_handle_t t, void * userp);
+
 /**
  * @brief               Set websocket authorization headers
  *

components/tcp_transport/transport_ws.c

@@ -63,6 +63,8 @@ typedef struct {
     char *sub_protocol;
     char *user_agent;
     char *headers;
+    ws_header_hook header_hook;
+    void * header_userp;
     char *auth;
     char *buffer;             /*!< Initial HTTP connection buffer, which may include data beyond the handshake headers, such as the next WebSocket packet*/
     size_t buffer_len;        /*!< The buffer length */
@@ -144,31 +146,6 @@ static int esp_transport_read_internal(transport_ws_t *ws, char *buffer, int len
     return to_read;
 }
 
-static char *trimwhitespace(char *str)
-{
-    char *end;
-
-    // Trim leading space
-    while (isspace((unsigned char)*str)) {
-        str++;
-    }
-
-    if (*str == 0) {
-        return str;
-    }
-
-    // Trim trailing space
-    end = str + strlen(str) - 1;
-    while (end > str && isspace((unsigned char)*end)) {
-        end--;
-    }
-
-    // Write new null terminator
-    *(end + 1) = '\0';
-
-    return str;
-}
-
 static int get_http_status_code(const char *buffer)
 {
     const char http[] = "HTTP/";
@@ -189,21 +166,6 @@ static int get_http_status_code(const char *buffer)
     return -1;
 }
 
-static char *get_http_header(char *buffer, const char *key)
-{
-    char *found = strcasestr(buffer, key);
-    if (found) {
-        found += strlen(key);
-        char *found_end = strstr(found, "\r\n");
-        if (found_end) {
-            *found_end = '\0'; // terminal string
-
-            return trimwhitespace(found);
-        }
-    }
-    return NULL;
-}
-
 static int ws_connect(esp_transport_handle_t t, const char *host, int port, int timeout_ms)
 {
     transport_ws_t *ws = esp_transport_get_context_data(t);
@@ -330,17 +292,67 @@ static int ws_connect(esp_transport_handle_t t, const char *host, int port, int
     if (ws->http_status_code == -1)  {
         ESP_LOGE(TAG, "HTTP upgrade failed");
         return -1;
-    } else if (WS_HTTP_TEMPORARY_REDIRECT(ws->http_status_code) || WS_HTTP_PERMANENT_REDIRECT(ws->http_status_code)) {
-        char * redir_host = get_http_header(ws->buffer, "Location:");
-        if (redir_host == NULL) {
+    }
+
+    const char *location = NULL;
+    int location_len = 0;
+
+    const char *server_key = NULL;
+    int server_key_len = 0;
+    const char * header_cursor = strnstr(ws->buffer, "\r\n", header_len);
+    if (!header_cursor){
+        ESP_LOGE(TAG, "HTTP Header locate failed");
+        return -1;
+    }
+    header_cursor += strlen("\r\n");
+
+    while(header_cursor < delim_ptr){
+        const char * end_of_line = strnstr(header_cursor, "\r\n", header_len - (header_cursor - ws->buffer));
+        if(!end_of_line){
+            ESP_LOGE(TAG, "HTTP Header walk failed");
+            return -1;
+        }
+        else if(end_of_line == header_cursor){
+            ESP_LOGD(TAG, "HTTP Header walk found end");
+            break;
+        }
+        int line_len = end_of_line - header_cursor;
+        ESP_LOGD(TAG, "HTTP Header walk line:%.*s", line_len, header_cursor);
+
+        // Check for Sec-WebSocket-Accept header
+        const char * header_sec_websocket_accept = "Sec-WebSocket-Accept: ";
+        size_t header_sec_websocket_accept_len = strlen(header_sec_websocket_accept);
+        if (line_len >= header_sec_websocket_accept_len && !strncasecmp(header_cursor, header_sec_websocket_accept, header_sec_websocket_accept_len)) {
+            ESP_LOGD(TAG, "found server-key");
+            server_key = header_cursor + header_sec_websocket_accept_len;
+            server_key_len = line_len - header_sec_websocket_accept_len;
+        }
+        else if (ws->header_hook) {
+            ws->header_hook(ws->header_userp, header_cursor, line_len);
+        }
+
+        // Check for Location: header
+        const char * header_location = "Location: ";
+        size_t header_location_len = strlen(header_location);
+        if (line_len >= header_location_len && !strncasecmp(header_cursor, header_location, header_location_len)) {
+            location = header_cursor + header_location_len;
+            location_len = line_len - header_location_len;
+        }
+
+        // Adjust cursor to the start of the next line
+        header_cursor += line_len;
+        header_cursor += strlen("\r\n");
+    }
+
+    if (WS_HTTP_TEMPORARY_REDIRECT(ws->http_status_code) || WS_HTTP_PERMANENT_REDIRECT(ws->http_status_code)) {
+        if (location == NULL || location_len <= 0) {
             ESP_LOGE(TAG, "Location header not found");
             return -1;
         }
-        ws->redir_host = strdup(redir_host);
+        ws->redir_host = strndup(location, location_len);
         return ws->http_status_code;
     }
 
-    char *server_key = get_http_header(ws->buffer, "Sec-WebSocket-Accept:");
     if (server_key == NULL) {
         ESP_LOGE(TAG, "Sec-WebSocket-Accept not found");
         return -1;
@@ -361,7 +373,7 @@ static int ws_connect(esp_transport_handle_t t, const char *host, int port, int
     esp_crypto_base64_encode(expected_server_key, sizeof(expected_server_key),  &outlen, expected_server_sha1, sizeof(expected_server_sha1));
     expected_server_key[ (outlen < sizeof(expected_server_key)) ? outlen : (sizeof(expected_server_key) - 1) ] = 0;
     ESP_LOGD(TAG, "server key=%s, send_key=%s, expected_server_key=%s", (char *)server_key, (char *)client_key, expected_server_key);
-    if (strcmp((char *)expected_server_key, (char *)server_key) != 0) {
+    if (strncmp((char *)expected_server_key, (char *)server_key, server_key_len) != 0) {
         ESP_LOGE(TAG, "Invalid websocket key");
         return -1;
     }
@@ -866,6 +878,26 @@ esp_err_t esp_transport_ws_set_headers(esp_transport_handle_t t, const char *hea
     return ESP_OK;
 }
 
+esp_err_t esp_transport_ws_set_header_hook(esp_transport_handle_t t, ws_header_hook hook)
+{
+    if (t == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    transport_ws_t *ws = esp_transport_get_context_data(t);
+    ws->header_hook = hook;
+    return ESP_OK;
+}
+
+esp_err_t esp_transport_ws_set_header_userp(esp_transport_handle_t t, void * userp)
+{
+    if (t == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    transport_ws_t *ws = esp_transport_get_context_data(t);
+    ws->header_userp = userp;
+    return ESP_OK;
+}
+
 esp_err_t esp_transport_ws_set_auth(esp_transport_handle_t t, const char *auth)
 {
     if (t == NULL) {
@@ -931,6 +963,14 @@ esp_err_t esp_transport_ws_set_config(esp_transport_handle_t t, const esp_transp
         err = esp_transport_ws_set_headers(t, config->headers);
         ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;)
     }
+    if (config->header_hook) {
+        err = esp_transport_ws_set_header_hook(t, config->header_hook);
+        ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;)
+    }
+    if (config->header_userp) {
+      err = esp_transport_ws_set_header_userp(t, config->header_userp);
+      ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;)
+    }
     if (config->auth) {
         err = esp_transport_ws_set_auth(t, config->auth);
         ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;)