HTTP AT Commands

[中文]

AT+HTTPCLIENT: Send HTTP Client Request

Set Command

Command:

AT+HTTPCLIENT=<opt>,<content-type>,<"url">,[<"host">],[<"path">],<transport_type>[,<"data">][,<"http_req_header">][,<"http_req_header">][...]

Response:

+HTTPCLIENT:<size>,<data>

OK

Parameters

  • <opt>: method of HTTP client request.
    • 1: HEAD
    • 2: GET
    • 3: POST
    • 4: PUT
    • 5: DELETE
  • <content-type>: data type of HTTP client request.
    • 0: application/x-www-form-urlencoded
    • 1: application/json
    • 2: multipart/form-data
    • 3: text/xml
  • <”url”>: HTTP URL. The parameter can override the <host> and <path> parameters if they are null.
  • <”host”>: domain name or IP address.
  • <”path”>: HTTP Path.
  • <transport_type>: HTTP Client transport type. Default: 1.
    • 1: HTTP_TRANSPORT_OVER_TCP
    • 2: HTTP_TRANSPORT_OVER_SSL
  • <”data”>: If <opt> is a POST request, this parameter holds the data you send to the HTTP server. If not, this parameter does not exist, which means there is no need to input a comma to indicate this parameter.
  • <http_req_header>: you can send more than one request header to the server.

Notes

  • If the url parameter is not null, HTTP client will use it and ignore the host parameter and path parameter; If the url parameter is omited or null string, HTTP client will use host parameter and path parameter.
  • In some released firmware, HTTP client commands are not supported (see ESP-AT Firmware Differences), but you can enable it by ./build.py menuconfig > Component config > AT > AT http command support and build the project (see Compile ESP-AT Project).

Example

// HEAD Request
AT+HTTPCLIENT=1,0,"http://httpbin.org/get","httpbin.org","/get",1

// GET Request
AT+HTTPCLIENT=2,0,"http://httpbin.org/get","httpbin.org","/get",1

// POST Request
AT+HTTPCLIENT=3,0,"http://httpbin.org/post","httpbin.org","/post",1,"field1=value1&field2=value2"

AT+HTTPGETSIZE: Get HTTP Resource Size

Set Command

Command:

AT+HTTPGETSIZE=<url>

Response:

+HTTPGETSIZE:<size>

OK

Parameters

  • <url>: HTTP URL.
  • <size>: HTTP resource size.

Note

  • In some released firmware, HTTP client commands are not supported (see ESP-AT Firmware Differences), but you can enable it by ./build.py menuconfig > Component config > AT > AT http command support and build the project (see Compile ESP-AT Project).

Example

AT+HTTPGETSIZE="http://www.baidu.com/img/bdlogo.gif"

AT+HTTPCPOST: Post HTTP data of specified length

Set Command

Command:

AT+HTTPCPOST=<url>,<length>[,<http_req_header_cnt>][,<http_req_header>..<http_req_header>]

Response:

OK
>

The symbol > indicates that AT is ready for receiving serial data, and you can enter the data now. When the requirement of message length determined by the parameter <length> is met, the transmission starts.

If the transmission is successful, AT returns:

SEND OK

Otherwise, it returns:

SEND FAIL

Parameters

  • <url>: HTTP URL.
  • <length>: HTTP data length to POST. The maximum length is equal to the system allocable heap size.
  • <http_req_header_cnt>: the number of <http_req_header> parameters.
  • [<http_req_header>]: you can send more than one request header to the server.

HTTP AT Error Codes

  • HTTP Client:

    HTTP Client Error Code Description
    0x7190 Bad Request
    0x7191 Unauthorized
    0x7192 Payment Required
    0x7193 Forbidden
    0x7194 Not Found
    0x7195 Method Not Allowed
    0x7196 Not Acceptable
    0x7197 Proxy Authentication Required
    0x7198 Request Timeout
    0x7199 Conflict
    0x719a Gone
    0x719b Length Required
    0x719c Precondition Failed
    0x719d Request Entity Too Large
    0x719e Request-URI Too Long
    0x719f Unsupported Media Type
    0x71a0 Requested Range Not Satisfiable
    0x71a1 Expectation Failed
  • HTTP Server:

    HTTP Server Error Code Description
    0x71f4 Internal Server Error
    0x71f5 Not Implemented
    0x71f6 Bad Gateway
    0x71f7 Service Unavailable
    0x71f8 Gateway Timeout
    0x71f9 HTTP Version Not Supported
  • HTTP AT:

    • The error code of command AT+HTTPCLIENT will be 0x7000+Standard HTTP Error Code (For more details about Standard HTTP/1.1 Error Code, see RFC 2616).
    • For example, if AT gets the HTTP error 404 when calling command AT+HTTPCLIENT, it will respond with error code of 0x7194 (hex(0x7000+404)=0x7194).