HTTP Server and Testing

Running Flask

Flask is a lightweight templating system but is also handy for quickly serving up static HTML and responding to POST/GET.

Install flask with pip install flask.

Create a python script file (server.py) and put this in the contents;

#!/usr/bin/env python

from flask import Flask, request, jsonify
import os
import os.path
import logging
import json

base_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), '..')
app = Flask(
    __name__,
    static_folder=os.path.join(base_path, 'web')
)

@app.route('/')
def root():
    return app.send_static_file('wifi.html')

@app.route("/ap.json", methods=["GET"])
def ap_json():
    with open(base_path+'\\tools\\ap.json') as json_file:
	    data = json.load(json_file)
    return jsonify(data)

@app.route("/status.json", methods=["GET"])
def status_json():
    with open(base_path+'\\tools\\status.json') as json_file:
	    data = json.load(json_file)
    return jsonify(data)

@app.route("/connect.json", methods=["POST"])
def json_example():
    if request.is_json:
        req = request.get_json()
        print(req)
        return "JSON received!", 200
    else:
        return "Request was not JSON", 400
		
app.run(host='0.0.0.0', debug=True)

ESP HTTPD Server

Legacy Changes

ESP8266 RTOS SDK sent error responses with helper functions;

esp_err_t httpd_resp_send_404(httpd_req_t *r);
esp_err_t httpd_resp_send_408(httpd_req_t *r);
esp_err_t httpd_resp_send_500(httpd_req_t *r);

Which calls a private function httpd_resp_send_err(r, HTTPD_404_NOT_FOUND);

case HTTPD_404_NOT_FOUND:
status = "404 Not Found";
msg    = "This URI doesn't exist";

httpd_resp_set_status   (req, status);
httpd_resp_set_type     (req, HTTPD_TYPE_TEXT);
httpd_resp_send         (req, msg, strlen(msg));

It also had these defines

#define HTTPD_200      "200 OK"                     /*!< HTTP Response 200 */
#define HTTPD_204      "204 No Content"             /*!< HTTP Response 204 */
#define HTTPD_207      "207 Multi-Status"           /*!< HTTP Response 207 */
#define HTTPD_400      "400 Bad Request"            /*!< HTTP Response 400 */
#define HTTPD_404      "404 Not Found"              /*!< HTTP Response 404 */
#define HTTPD_408      "408 Request Timeout"        /*!< HTTP Response 408 */
#define HTTPD_500      "500 Internal Server Error"  /*!< HTTP Response 500 */

So you can send other errors;

httpd_resp_set_status(req, HTTPD_500);
httpd_resp_send(req, STR, strlen(STR));

ESP-IDF has consolidated this function and made it a public function httpd_resp_send_err(httpd_req_t *req, httpd_err_code_t error, const char *msg) with an enumeration

typedef enum {
    HTTPD_500_INTERNAL_SERVER_ERROR = 0,
    HTTPD_501_METHOD_NOT_IMPLEMENTED,
    HTTPD_505_VERSION_NOT_SUPPORTED,
    HTTPD_400_BAD_REQUEST,
    HTTPD_404_NOT_FOUND,
    HTTPD_405_METHOD_NOT_ALLOWED,
    HTTPD_408_REQ_TIMEOUT,
    HTTPD_411_LENGTH_REQUIRED,
    HTTPD_414_URI_TOO_LONG,
    HTTPD_431_REQ_HDR_FIELDS_TOO_LARGE,
    HTTPD_ERR_CODE_MAX
} httpd_err_code_t;

It supports the old helper functions as well

static inline esp_err_t httpd_resp_send_404(httpd_req_t *r) {
    return httpd_resp_send_err(r, HTTPD_404_NOT_FOUND, NULL);
}