HTTP client AT commands

HTTP client connection #XHTTPCCON
HTTP request #XHTTPCREQ
HTTP response #XHTTPCRSP
- Unsolicited notification

The following commands list contains the HTTP client AT commands.

HTTP client connection #XHTTPCCON 

The #XHTTPCCON command allows you to connect to and disconnect from an HTTP server and to show the HTTP connection information.

Set command 

The set command allows you to connect to and disconnect from an HTTP server.

Syntax

AT#XHTTPCCON=<op>[,<host>,<port>[,<sec_tag>]]

The <op> parameter can accept one of the following values:
- 0 - Disconnect from the HTTP server
- 1 - Connect to the HTTP server for IP protocol family version 4
- 2 - Connect to the HTTP server for IP protocol family version 6
The <host> parameter is a string. It represents the HTTP server hostname.
The <port> parameter is an unsigned 16-bit integer (0 - 65535). It represents the HTTP server port.
The <sec_tag> parameter is an integer. It indicates to the modem the credential of the security tag used for establishing a secure connection.

Response syntax

#XHTTPCCON=<state>

The <state> value can assume one of the following values:
- 0 - Disconnected
- 1 - Connected

Example

AT#XHTTPCCON=1,"postman-echo.com",80
#XHTTPCCON:1
OK

Read command 

The read command shows the HTTP connection information.

Syntax

AT#XHTTPCCON?

Response syntax

XHTTPCCON: <state>,<host>,<port>[,<sec_tag>]]

Example

AT#XHTTPCCON?
#XHTTPCCON: 1,"postman-echo.com",80
OK

Test command 

The test command tests the existence of the command and provides information about the type of its subparameters.

Example

AT#XHTTPCCON=?
#XHTTPCCON: (0,1),<host>,<port>,<sec_tag>
OK

HTTP request #XHTTPCREQ 

The #XHTTPCREQ command allows you to send an HTTP request to the server.

Set command 

The set command allows you to send an HTTP request to the server.

Syntax

AT#XHTTPCREQ=<method>,<resource>,<headers>[,<payload_length>]

The <method> is a string. It represents the request method string.
The <resource> is a string. It represents the target resource to apply the request.
The <headers> is a string. It represents the header field of the request. Each header field should end with <CR><LF>. Any occurrence of “\r\n” (4 bytes) inside is replaced by <CR><LF> (2 bytes).
The <payload_length> is an integer. It represents the length of the payload. If payload_length is greater than 0, the SLM will enter data mode and expect the upcoming UART input data as payload. The SLM will then send the payload to the HTTP server until the payload_length bytes are sent. To abort sending the payload, terminate data mode by sending the terminator string defined in CONFIG_SLM_DATAMODE_TERMINATOR. The default pattern string is “+++”.

Response syntax

#XHTTPCREQ:<state>

The <state> value can assume one of the following values:

0 - Request sent successfully
1 - Wait for payload data
Negative integer - Error code

Example

The following example sends a GET request to retrieve data from the server without any optional header.

AT#XHTTPCREQ="GET","/get?foo1=bar1&foo2=bar2",""

OK


#XHTTPCREQ: 0

#XHTTPCRSP:341,0
HTTP/1.1 200 OK
Date: Thu, 11 Mar 2021 04:36:19 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 244
Connection: keep-alive
ETag: W/"f4-ZKlqfH53aEj3f4zb0kDtYvHD+XU"
Vary: Accept-Encoding
set-cookie: sails.sid=s%3AHGcBwpqlDDUZhU16VzuQkfTMhWhA4W1T.%2Bgm1%2BezKGo2JnWxaB5yYDo%2FNh0NbnJzJjEnkMcrfdEI; Path=/; HttpOnly


#XHTTPCRSP:243,0
{"args":{"foo1":"bar1","foo2":"bar2"},"headers":{"x-forwarded-proto":"http","x-forwarded-port":"80","host":"postman-echo.com","x-amzn-trace-id":"Root=1-60499e43-67a96f1e18fec45b1db78c25"},"url":"http://postman-echo.com/get?foo1=bar1&foo2=bar2"
#XHTTPCRSP:1,0
}
#XHTTPCRSP:0,1

The following example sends a GET request with some headers that are delimited by “\r\n”.

AT#XHTTPCREQ="GET","/instruments/150771004/temperature-values/?page=1 HTTP/1.1","Host: demo.abc.com\r\nAccept: application/vnd.api+json\r\nAuthorization: Basic ZGVtbzpkZxxx\r\n"

OK

Read command 

The read command is not supported.

Test command 

The test command is not supported.

HTTP response #XHTTPCRSP 

The #XHTTPCRSP is an unsolicited notification that indicates that a part of the HTTP response has been received.

Unsolicited notification 

It indicates that a part of the HTTP response has been received.

Syntax

#XHTTPCRSP=<byte_received>,<state><CR><LF><response>

The <byte_received> is an integer. It represents the length of a partially received HTTP response.
The <state> value can assume one of the following values:
- 0 - There is more HTTP response data to come.
- 1 - The entire HTTP response has been received.
The <response> is the raw data of the HTTP response, including headers and body.

Example

The following example sends a PUT request to send data in JSON format to the server, with an optional header.

AT#XHTTPCCON=1,"example.com",80
#XHTTPCCON: 1

OK
AT#XHTTPCREQ="PUT","/iot/v1/device/12345678901","User-Agent: curl/7.58.0
accept: */*
CK: DEADBEEFDEADBEEFDE
Content-Type: application/json
Content-Length: 224
",224
OK

#XHTTPCREQ: 1
{"id":"123456789","name":"iamchanged","desc":"My Hygrometer","type":"general","uri":"http://a.b.c.d/hygrometer","lat":24.95,"lon":121.16,"attributes":[{"key":"label","value":"thermometer"},{"key":"region","value":"Taiwan"}]}
OK

#XHTTPCREQ: 0
#XHTTPCRSP:408,0
HTTP/1.1 200
Server: nginx/1.17.3
Date: Wed, 17 Mar 2021 08:43:56 GMT
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
X-Application-Context: iotapi:pob:80
Vary: Origin
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: 0
X-Frame-Options: DENY


#XHTTPCRSP:22,0
{"id":"12345678901"}

#XHTTPCRSP:0,1