esp-idf/examples/protocols/http_server/simple/README.md
mjcross 03901946ba Explain how to fix 'httpd_parse: header too long'
Because this is the 'simple' server example, it is probably where users will start out to understand the HTTP Server API; and also where they might come if they are having problems.
So I think it is useful to explain to users what to do if they see "httpd_parse: parse_block: request URI/header too long", which can easily happen if they submit a POST from an HTML form (for example). That certainly would have helped me!

Merges https://github.com/espressif/esp-idf/pull/6547

Signed-off-by: Shubham Kulkarni <shubham.kulkarni@espressif.com>
2021-03-04 04:08:47 +00:00

2.1 KiB

Simple HTTPD Server Example

The Example consists of HTTPD server demo with demostration of URI handling : 1. URI \hello for GET command returns "Hello World!" message 2. URI \echo for POST command echoes back the POSTed message

  • Open the project configuration menu (idf.py menuconfig) to configure Wi-Fi or Ethernet. See "Establishing Wi-Fi or Ethernet Connection" section in examples/protocols/README.md for more details.

  • In order to test the HTTPD server persistent sockets demo :

    1. compile and burn the firmware idf.py -p PORT flash
    2. run idf.py -p PORT monitor and note down the IP assigned to your ESP module. The default port is 80
    3. test the example :
      • run the test script : "python scripts/client.py <IP> <port> <MSG>"
        • the provided test script first does a GET \hello and displays the response
        • the script does a POST to \echo with the user input <MSG> and displays the response
      • or use curl (asssuming IP is 192.168.43.130):
        1. "curl 192.168.43.130:80/hello" - tests the GET "\hello" handler
        2. "curl -X POST --data-binary @anyfile 192.168.43.130:80/echo > tmpfile"
          • "anyfile" is the file being sent as request body and "tmpfile" is where the body of the response is saved
          • since the server echoes back the request body, the two files should be same, as can be confirmed using : "cmp anyfile tmpfile"
        3. "curl -X PUT -d "0" 192.168.43.130:80/ctrl" - disable /hello and /echo handlers
        4. "curl -X PUT -d "1" 192.168.43.130:80/ctrl" - enable /hello and /echo handlers
  • If the server log shows "httpd_parse: parse_block: request URI/header too long", especially when handling POST requests, then you probably need to increase HTTPD_MAX_REQ_HDR_LEN, which you can find in the project configuration menu (idf.py menuconfig): Component config -> HTTP Server -> Max HTTP Request Header Length

See the README.md file in the upper level 'examples' directory for more information about examples.