OVMS3-idf/components/esp_http_server/src/httpd_uri.c
Anurag Kar 28412d8cb6 http_server : Added feature for invoking user configurable handlers during server errors
Added APIs :
  * httpd_resp_send_err()        : for sending HTTP error responses for error codes given by httpd_err_code_t. It uses TCP_NODELAY option to ensure that HTTP error responses reach the client before socket is closed.
  * httpd_register_err_handler() : for registering HTTP error handler functions of type httpd_err_handler_func_t.

The default behavior, on encountering errors during processing of HTTP requests, is now to send HTTP error response (if possible) and close the underlying socket. User configurable handlers can be used to override this behavior for each error individually (except for 500 Internal Server Error).

Also fixed some typos.

Closes https://github.com/espressif/esp-idf/issues/3005
2019-02-25 09:13:39 +00:00

317 lines
11 KiB
C

// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <errno.h>
#include <esp_log.h>
#include <esp_err.h>
#include <http_parser.h>
#include <esp_http_server.h>
#include "esp_httpd_priv.h"
static const char *TAG = "httpd_uri";
static bool httpd_uri_match_simple(const char *uri1, const char *uri2, size_t len2)
{
return strlen(uri1) == len2 && // First match lengths
(strncmp(uri1, uri2, len2) == 0); // Then match actual URIs
}
bool httpd_uri_match_wildcard(const char *template, const char *uri, size_t len)
{
const size_t tpl_len = strlen(template);
size_t exact_match_chars = tpl_len;
/* Check for trailing question mark and asterisk */
const char last = (const char) (tpl_len > 0 ? template[tpl_len - 1] : 0);
const char prevlast = (const char) (tpl_len > 1 ? template[tpl_len - 2] : 0);
const bool asterisk = last == '*' || (prevlast == '*' && last == '?');
const bool quest = last == '?' || (prevlast == '?' && last == '*');
/* Minimum template string length must be:
* 0 : if neither of '*' and '?' are present
* 1 : if only '*' is present
* 2 : if only '?' is present
* 3 : if both are present
*
* The expression (asterisk + quest*2) serves as a
* case wise generator of these length values
*/
/* abort in cases such as "?" with no preceding character (invalid template) */
if (exact_match_chars < asterisk + quest*2) {
return false;
}
/* account for special characters and the optional character if "?" is used */
exact_match_chars -= asterisk + quest*2;
if (len < exact_match_chars) {
return false;
}
if (!quest) {
if (!asterisk && len != exact_match_chars) {
/* no special characters and different length - strncmp would return false */
return false;
}
/* asterisk allows arbitrary trailing characters, we ignore these using
* exact_match_chars as the length limit */
return (strncmp(template, uri, exact_match_chars) == 0);
} else {
/* question mark present */
if (len > exact_match_chars && template[exact_match_chars] != uri[exact_match_chars]) {
/* the optional character is present, but different */
return false;
}
if (strncmp(template, uri, exact_match_chars) != 0) {
/* the mandatory part differs */
return false;
}
/* Now we know the URI is longer than the required part of template,
* the mandatory part matches, and if the optional character is present, it is correct.
* Match is OK if we have asterisk, i.e. any trailing characters are OK, or if
* there are no characters beyond the optional character. */
return asterisk || len <= exact_match_chars + 1;
}
}
/* Find handler with matching URI and method, and set
* appropriate error code if URI or method not found */
static httpd_uri_t* httpd_find_uri_handler(struct httpd_data *hd,
const char *uri, size_t uri_len,
httpd_method_t method,
httpd_err_code_t *err)
{
if (err) {
*err = HTTPD_404_NOT_FOUND;
}
for (int i = 0; i < hd->config.max_uri_handlers; i++) {
if (!hd->hd_calls[i]) {
break;
}
ESP_LOGD(TAG, LOG_FMT("[%d] = %s"), i, hd->hd_calls[i]->uri);
/* Check if custom URI matching function is set,
* else use simple string compare */
if (hd->config.uri_match_fn ?
hd->config.uri_match_fn(hd->hd_calls[i]->uri, uri, uri_len) :
httpd_uri_match_simple(hd->hd_calls[i]->uri, uri, uri_len)) {
/* URIs match. Now check if method is supported */
if (hd->hd_calls[i]->method == method) {
/* Match found! */
if (err) {
/* Unset any error that may
* have been set earlier */
*err = 0;
}
return hd->hd_calls[i];
}
/* URI found but method not allowed.
* If URI is found later then this
* error must be set to 0 */
if (err) {
*err = HTTPD_405_METHOD_NOT_ALLOWED;
}
}
}
return NULL;
}
esp_err_t httpd_register_uri_handler(httpd_handle_t handle,
const httpd_uri_t *uri_handler)
{
if (handle == NULL || uri_handler == NULL) {
return ESP_ERR_INVALID_ARG;
}
struct httpd_data *hd = (struct httpd_data *) handle;
/* Make sure another handler with matching URI and method
* is not already registered. This will also catch cases
* when a registered URI wildcard pattern already accounts
* for the new URI being registered */
if (httpd_find_uri_handler(handle, uri_handler->uri,
strlen(uri_handler->uri),
uri_handler->method, NULL) != NULL) {
ESP_LOGW(TAG, LOG_FMT("handler %s with method %d already registered"),
uri_handler->uri, uri_handler->method);
return ESP_ERR_HTTPD_HANDLER_EXISTS;
}
for (int i = 0; i < hd->config.max_uri_handlers; i++) {
if (hd->hd_calls[i] == NULL) {
hd->hd_calls[i] = malloc(sizeof(httpd_uri_t));
if (hd->hd_calls[i] == NULL) {
/* Failed to allocate memory */
return ESP_ERR_HTTPD_ALLOC_MEM;
}
/* Copy URI string */
hd->hd_calls[i]->uri = strdup(uri_handler->uri);
if (hd->hd_calls[i]->uri == NULL) {
/* Failed to allocate memory */
free(hd->hd_calls[i]);
return ESP_ERR_HTTPD_ALLOC_MEM;
}
/* Copy remaining members */
hd->hd_calls[i]->method = uri_handler->method;
hd->hd_calls[i]->handler = uri_handler->handler;
hd->hd_calls[i]->user_ctx = uri_handler->user_ctx;
ESP_LOGD(TAG, LOG_FMT("[%d] installed %s"), i, uri_handler->uri);
return ESP_OK;
}
ESP_LOGD(TAG, LOG_FMT("[%d] exists %s"), i, hd->hd_calls[i]->uri);
}
ESP_LOGW(TAG, LOG_FMT("no slots left for registering handler"));
return ESP_ERR_HTTPD_HANDLERS_FULL;
}
esp_err_t httpd_unregister_uri_handler(httpd_handle_t handle,
const char *uri, httpd_method_t method)
{
if (handle == NULL || uri == NULL) {
return ESP_ERR_INVALID_ARG;
}
struct httpd_data *hd = (struct httpd_data *) handle;
for (int i = 0; i < hd->config.max_uri_handlers; i++) {
if (!hd->hd_calls[i]) {
break;
}
if ((hd->hd_calls[i]->method == method) && // First match methods
(strcmp(hd->hd_calls[i]->uri, uri) == 0)) { // Then match URI string
ESP_LOGD(TAG, LOG_FMT("[%d] removing %s"), i, hd->hd_calls[i]->uri);
free((char*)hd->hd_calls[i]->uri);
free(hd->hd_calls[i]);
hd->hd_calls[i] = NULL;
/* Shift the remaining non null handlers in the array
* forward by 1 so that order of insertion is maintained */
for (i += 1; i < hd->config.max_uri_handlers; i++) {
if (!hd->hd_calls[i]) {
break;
}
hd->hd_calls[i-1] = hd->hd_calls[i];
}
/* Nullify the following non null entry */
hd->hd_calls[i-1] = NULL;
return ESP_OK;
}
}
ESP_LOGW(TAG, LOG_FMT("handler %s with method %d not found"), uri, method);
return ESP_ERR_NOT_FOUND;
}
esp_err_t httpd_unregister_uri(httpd_handle_t handle, const char *uri)
{
if (handle == NULL || uri == NULL) {
return ESP_ERR_INVALID_ARG;
}
struct httpd_data *hd = (struct httpd_data *) handle;
bool found = false;
int i = 0, j = 0; // For keeping count of removed entries
for (; i < hd->config.max_uri_handlers; i++) {
if (!hd->hd_calls[i]) {
break;
}
if (strcmp(hd->hd_calls[i]->uri, uri) == 0) { // Match URI strings
ESP_LOGD(TAG, LOG_FMT("[%d] removing %s"), i, uri);
free((char*)hd->hd_calls[i]->uri);
free(hd->hd_calls[i]);
hd->hd_calls[i] = NULL;
found = true;
j++; // Update count of removed entries
} else {
/* Shift the remaining non null handlers in the array
* forward by j so that order of insertion is maintained */
hd->hd_calls[i-j] = hd->hd_calls[i];
}
}
/* Nullify the following non null entries */
for (int k = (i - j); k < i; k++) {
hd->hd_calls[k] = NULL;
}
if (!found) {
ESP_LOGW(TAG, LOG_FMT("no handler found for URI %s"), uri);
}
return (found ? ESP_OK : ESP_ERR_NOT_FOUND);
}
void httpd_unregister_all_uri_handlers(struct httpd_data *hd)
{
for (unsigned i = 0; i < hd->config.max_uri_handlers; i++) {
if (!hd->hd_calls[i]) {
break;
}
ESP_LOGD(TAG, LOG_FMT("[%d] removing %s"), i, hd->hd_calls[i]->uri);
free((char*)hd->hd_calls[i]->uri);
free(hd->hd_calls[i]);
hd->hd_calls[i] = NULL;
}
}
esp_err_t httpd_uri(struct httpd_data *hd)
{
httpd_uri_t *uri = NULL;
httpd_req_t *req = &hd->hd_req;
struct http_parser_url *res = &hd->hd_req_aux.url_parse_res;
/* For conveying URI not found/method not allowed */
httpd_err_code_t err = 0;
ESP_LOGD(TAG, LOG_FMT("request for %s with type %d"), req->uri, req->method);
/* URL parser result contains offset and length of path string */
if (res->field_set & (1 << UF_PATH)) {
uri = httpd_find_uri_handler(hd, req->uri + res->field_data[UF_PATH].off,
res->field_data[UF_PATH].len, req->method, &err);
}
/* If URI with method not found, respond with error code */
if (uri == NULL) {
switch (err) {
case HTTPD_404_NOT_FOUND:
ESP_LOGW(TAG, LOG_FMT("URI '%s' not found"), req->uri);
return httpd_req_handle_err(req, HTTPD_404_NOT_FOUND);
case HTTPD_405_METHOD_NOT_ALLOWED:
ESP_LOGW(TAG, LOG_FMT("Method '%d' not allowed for URI '%s'"),
req->method, req->uri);
return httpd_req_handle_err(req, HTTPD_405_METHOD_NOT_ALLOWED);
default:
return ESP_FAIL;
}
}
/* Attach user context data (passed during URI registration) into request */
req->user_ctx = uri->user_ctx;
/* Invoke handler */
if (uri->handler(req) != ESP_OK) {
/* Handler returns error, this socket should be closed */
ESP_LOGW(TAG, LOG_FMT("uri handler execution failed"));
return ESP_FAIL;
}
return ESP_OK;
}