Not sure I know enough to give you the best answer, but here's an attempt anyway...
The example for http_server has a function to return 'Hello World!' to the browser if you try to visit <esp32-ip-address>/hello :
Code: Select all
/* An HTTP GET handler */
esp_err_t hello_get_handler(httpd_req_t *req)
{
char* buf;
size_t buf_len;
/* Get header value string length and allocate memory for length + 1,
* extra byte for null termination */
buf_len = httpd_req_get_hdr_value_len(req, "Host") + 1;
if (buf_len > 1) {
buf = malloc(buf_len);
/* Copy null terminated value string into buffer */
if (httpd_req_get_hdr_value_str(req, "Host", buf, buf_len) == ESP_OK) {
ESP_LOGI(TAG, "Found header => Host: %s", buf);
}
free(buf);
}
buf_len = httpd_req_get_hdr_value_len(req, "Test-Header-2") + 1;
if (buf_len > 1) {
buf = malloc(buf_len);
if (httpd_req_get_hdr_value_str(req, "Test-Header-2", buf, buf_len) == ESP_OK) {
ESP_LOGI(TAG, "Found header => Test-Header-2: %s", buf);
}
free(buf);
}
buf_len = httpd_req_get_hdr_value_len(req, "Test-Header-1") + 1;
if (buf_len > 1) {
buf = malloc(buf_len);
if (httpd_req_get_hdr_value_str(req, "Test-Header-1", buf, buf_len) == ESP_OK) {
ESP_LOGI(TAG, "Found header => Test-Header-1: %s", buf);
}
free(buf);
}
/* Read URL query string length and allocate memory for length + 1,
* extra byte for null termination */
buf_len = httpd_req_get_url_query_len(req) + 1;
if (buf_len > 1) {
buf = malloc(buf_len);
if (httpd_req_get_url_query_str(req, buf, buf_len) == ESP_OK) {
ESP_LOGI(TAG, "Found URL query => %s", buf);
char param[32];
/* Get value of expected key from query string */
if (httpd_query_key_value(buf, "query1", param, sizeof(param)) == ESP_OK) {
ESP_LOGI(TAG, "Found URL query parameter => query1=%s", param);
}
if (httpd_query_key_value(buf, "query3", param, sizeof(param)) == ESP_OK) {
ESP_LOGI(TAG, "Found URL query parameter => query3=%s", param);
}
if (httpd_query_key_value(buf, "query2", param, sizeof(param)) == ESP_OK) {
ESP_LOGI(TAG, "Found URL query parameter => query2=%s", param);
}
}
free(buf);
}
/* Set some custom headers */
httpd_resp_set_hdr(req, "Custom-Header-1", "Custom-Value-1");
httpd_resp_set_hdr(req, "Custom-Header-2", "Custom-Value-2");
/* Send response with custom headers and body set as the
* string passed in user context*/
const char* resp_str = (const char*) req->user_ctx;
httpd_resp_send(req, resp_str, strlen(resp_str));
/* After sending the HTTP response the old HTTP request
* headers are lost. Check if HTTP request headers can be read now. */
if (httpd_req_get_hdr_value_len(req, "Host") == 0) {
ESP_LOGI(TAG, "Request headers lost");
}
return ESP_OK;
}
httpd_uri_t hello = {
.uri = "/hello",
.method = HTTP_GET,
.handler = hello_get_handler,
/* Let's pass response string in user
* context to demonstrate it's usage */
.user_ctx = "Hello World!"
};
Now, ignore all the header and query parsing and look at this section:
Code: Select all
/* Send response with custom headers and body set as the
* string passed in user context*/
const char* resp_str = (const char*) req->user_ctx;
httpd_resp_send(req, resp_str, strlen(resp_str));
user_ctx is passed by the handler and contains 'Hello World!' - this is what appears on your browser if you hit the right URL. Seems to me that replacing this text in .user_ctx with some actual HTML should do the trick.
Now, to my inexperienced mind, it's messy as hell - but then it's enough to get you started. Once that's up and running, you can look at using the ESP-IDF file system (SPIFFS?) to serve up HTML, CSS and JS files to the browser. At least, that's what I'll be doing as soon as I get round to it!
