HTTP AT Examples

[中文]

This document provides detailed command examples to illustrate how to utilize HTTP AT Commands on ESP32-C2.

Important

Currently ESP-AT only supports some HTTP client functions.

The HEAD method of HTTP client

In this example, the HTTP server is http://httpbin.org.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Send an HTTP HEAD request. Set opt to 1 (HEAD method), url to http://httpbin.org/get and transport_type to 1 (HTTP_TRANSPORT_OVER_TCP).

    Command:

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

    Response:

    +HTTPCLIENT:35, Date: Sun, 26 Sep 2021 06:59:13 GMT
+HTTPCLIENT:30, Content-Type: application/json
+HTTPCLIENT:19, Content-Length: 329
+HTTPCLIENT:22, Connection: keep-alive
+HTTPCLIENT:23, Server: gunicorn/19.9.0
+HTTPCLIENT:30, Access-Control-Allow-Origin: *
+HTTPCLIENT:38, Access-Control-Allow-Credentials: true

OK

    Note:

    • The HTTP header information you obtain may be different from those in the above response.

The GET method of HTTP client

This example describes how to download an image file in JPG format. The image link is https://www.espressif.com/sites/all/themes/espressif/images/about-us/solution-platform.jpg.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Send an HTTP GET request. Set opt to 2 (GET method), url to https://www.espressif.com/sites/all/themes/espressif/images/about-us/solution-platform.jpg and transport_type to 2 (HTTP_TRANSPORT_OVER_SSL).

    Command:

    AT+HTTPCLIENT=2,0,"https://www.espressif.com/sites/all/themes/espressif/images/about-us/solution-platform.jpg",,,2

    Response:

    +HTTPCLIENT:512,<0xff><0xd8><0xff><0xe2><0x0c>XICC_PROFILE<break>
<0x01><0x01><break>
<break>
<0x0c>HLino<0x02><0x10><break>
<break>
mntrRGB XYZ <0x07><0xce><break>
<0x02><break>
...
+HTTPCLIENT:512,<0xeb><0xe2>v<0xcb><0x98>-<0xf8><0x8a><0xae><0xf3><0xc8><0xb6><0xa8><0x86><0x02>j<0x06><0xe2>
"<0xaa>*p<0x7f>2",h<0x12>N<0xa5><0x1e><0xd2>bp<0xea><0x1e><0xf5><0xa3>x<0xa6>J<0x14>Ti<0xc3>m<0x1a>m<0x94>T<0xe1>I<0xb6><0x90><0xdc>_<0x11>QU;<0x94><0x97><0xcb><0xdd><0xc7><0xc6><0x85><0xd7>U<0x02><0xc9>W<0xa4><0xaa><0xa1><0xa1><0x08>hB<0x1a><0x10><0x86><0x84>!<0xa1><0x08>hB<0x1a><0x10><0x9b><0xb9>K<0xf5>5<0x95>5-=<0x8a><0xcb><0xce><0xe0><0x91><0xf0>m<0xa9><0x04>C<0xde>k<0xe7><0xc2>v<H|<0xaf><0xb8>L<0x91>=<0xda>_<0x94><0xde><0xd0><0xa9><0xc0><0xdd>8<0x9a>B<0xaa><0x1a><0x10><0x86><0x84>$<0xf4><0xd6><0xf2><0xa3><0x92><0xe7><0xa8>I<0xa3>b<0x1f>)<0xe1>z<0xc4>y<0xae><0xca><0xed><0xec><0x1e>|^<0xd7>E<0xa2>_<0x13><0x9e>;{|<0xb5>Q<0x97><0xa5>P<0xdf><0xa1>#3vn<0x1b><0xc3>-<0x92><0xe2>dIn<0x9c><0xb8>
<0xc7><0xa9><0xc6>(<0xe0><0xd3>i-<0x9e>@<0xbb><0xcc><0x88><0xd5>K<0xe3><0xf0>O<0x9f>Km<0xb3>h<0xa8>omR<0xfe><0x8b><0xf9><0xa4><0xa6><0xff><break>
aU<0xdf><0xf3><0xa3>:A<0xe2>UG<0x04>k<0xaa>*<0xa1><0xa1><0x0b><0xca><0xec><0xd8>Q<0xfb><0xbc>yqY<0xec><0xfb>?<0x16>CM<0xf6>|}<0xae><0xf3><0x1e><0xdf>%<0xf8><0xe8><0xb1>B<0x8f>[<0xb3>><0x04><0xec><0xeb>f<0x06><0x1c><0xe8><0x92><0xc9><0x8c><0xb0>I<0xd1><0x8b>%<0x99><0x04><0xd0><0xbb>s<0x8b>xj<0xe2>4f<0xa0><0x8e>+E<0xda><0xab><0xc7>=<0xab><0xc7><0xb9>xz1f<0xba><0xfd>_e6<0xff><break>
(w<0xa7>b<0xe3>m<0xf0>|<0x82><0xc9><0xfb><0x8b><0xac>r<0x95><0x94><0x96><0xd9>i<0xe9>RVA<0x91><0x83><0x8b>M'<0x86><0x8f><0xa3>A<0xd8><0xd8>"r"<0x8a><0xa8><0x9e>zl=<0xcd><0x16><0x07>D<0xa2><0xd0>u(<0xc2><0x8b><0x0b><0xc4><0xf1><0x87><0x9c><0x93><0x8f><0xe3><0xd5>U<0x12>]<0x8e><0x91>]<0x91><0x06>#l<0xbe><0xf4>t0?<0xd7><0x85><GEM<0xb1>%<0xee>UUT<0xe7><0xdf><0xa0><0xb9><0xce><0xe2>U@<0x03><0x82>S<0xe9>*<0xa8>hB<0x1a><0x10><0xa1><0xaf>V<0x19>U<0x9d><0xb3>x<0xa6><0xc7><0xe2><0x86><0x8e>d[<0x89>e<0x05>l<0x80>H<0x91>#<0xd2><0x8c><0xe1>j<0x1b>rH<0x04><0x89><0x98><0xd3>lZW]q><0xc2><';<0x93><0xb4><0xf5>&<0x9d><0xa0>^Wp<0xa9>6`<0xe2>T<0xa2><0xc2><0xb1>*<0xbc><0x13><0x13><0xa0><0xc4>)<0x83><0xb6><0xbe><0x86><0xb9><0x88>-<0x1a>

OK

The POST method of HTTP client (suitable for POST small amount of data)

In this example, the HTTP server is http://httpbin.org and the data type is application/json.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Send an HTTP POST request. Set opt to 3 (POST method), url to http://httpbin.org/post, content-type to 1 (application/json) and transport_type to 1 (HTTP_TRANSPORT_OVER_TCP).

    Command:

    AT+HTTPCLIENT=3,1,"http://httpbin.org/post",,,1,"{\"form\":{\"purpose\":\"test\"}}"

    Response:

    +HTTPCLIENT:282,{
  "args": {},
  "data": "{\"form\":{\"purpose\":\"test\"}}",
  "files": {},
  "form": {},
  "headers": {
    "Content-Length": "27",
    "Content-Type": "application/json",
    "Host": "httpbin.org",
    "User-Agent": "ESP32 HTTP Client/1.0",
    "X-Amzn-Trace-Id": "Root=
+HTTPCLIENT:173,1-61503a3f-4b16b71918855b97614c5dfb"
  },
  "json": {
    "form": {
      "purpose": "test"
    }
  },
  "origin": "20.187.154.207",
  "url": "http://httpbin.org/post"
}


OK

    Note:

    • The results you obtain may be different from those in the above response.

The POST method of HTTP client (recommended method)

If the amount of data you post is relatively large, and the length of a single AT command has exceeded the threshold of 256, it is recommended that you use the AT+HTTPCPOST command.

In this example, the HTTP server is http://httpbin.org and the data type is application/json.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Post HTTP data of specified length. The command specifies that the number of HTTP header fields is 2, which are connection field and content-type field respectively. connection is keep-alive and content-type is application/json.

    Assume the JSON data you want to post is of 427 bytes as follows.

    {"headers": {"Accept": "application/json","Accept-Encoding": "gzip, deflate","Accept-Language": "en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7","Content-Length": "0","Host": "httpbin.org","Origin": "http://httpbin.org","Referer": "http://httpbin.org/","User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36","X-Amzn-Trace-Id": "Root=1-6150581e-1ad4bd5254b4bf5218070413"}}

    Command:

    AT+HTTPCPOST="http://httpbin.org/post",427,2,"connection: keep-alive","content-type: application/json"

    Response:

    OK

>

    This response indicates that AT is ready for receiving serial data. You should enter the 427-byte data mentioned above, and when the data length reaches the <length> value, data transmission starts.

    +HTTPCPOST:281,{
  "args": {},
  "data": "{\"headers\": {\"Accept\": \"application/json\",\"Accept-Encoding\": \"gzip, deflate\",\"Accept-Language\": \"en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7\",\"Content-Length\": \"0\",\"Host\": \"httpbin.org\",\"Origin\": \"http://httpbin.org\",\"Referer\": \"htt
+HTTPCPOST:512,p://httpbin.org/\",\"User-Agent\": \"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36\",\"X-Amzn-Trace-Id\": \"Root=1-6150581e-1ad4bd5254b4bf5218070413\"}}",
  "files": {},
  "form": {},
  "headers": {
    "Content-Length": "427",
    "Content-Type": "application/json",
    "Host": "httpbin.org",
    "User-Agent": "ESP32 HTTP Client/1.0",
    "X-Amzn-Trace-Id": "Root=1-61505e76-278b5c267aaf55842bd58b32"
  },
  "json": {
    "headers": {

+HTTPCPOST:512,"Accept": "application/json",
      "Accept-Encoding": "gzip, deflate",
      "Accept-Language": "en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7",
      "Content-Length": "0",
      "Host": "httpbin.org",
      "Origin": "http://httpbin.org",
      "Referer": "http://httpbin.org/",
      "User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36",
      "X-Amzn-Trace-Id": "Root=1-6150581e-1ad4bd5254b4bf5218070413"
    }
  },
  "origin": "20.187.154
+HTTPCPOST:45,.207",
  "url": "http://httpbin.org/post"
}


SEND OK

    Note:

    • After AT outputs the > character, the special characters in the HTTP body do not need to be escaped using the escape character, and the data do not need to end with a new line (CR-LF).

The PUT method of HTTP client (suitable for no data put)

In this example, the HTTP server is http://httpbin.org. PUT request supports Query String Parameters mode.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Send an HTTP PUT request. Set opt to 4 (PUT method), url to http://httpbin.org/put, and transport_type to 1 (HTTP_TRANSPORT_OVER_TCP).

    Command:

    AT+HTTPCLIENT=4,0,"http://httpbin.org/put?user=foo",,,1

    Response:

    +HTTPCLIENT:282,{
  "args": {
    "user": "foo"
  },
  "data": "",
  "files": {},
  "form": {},
  "headers": {
    "Content-Length": "0",
    "Content-Type": "application/x-www-form-urlencoded",
    "Host": "httpbin.org",
    "User-Agent": "ESP32 HTTP Client/1.0",
    "X-Amzn-Trace-Id": "R
+HTTPCLIENT:140,oot=1-61503d41-1dd8cbe0056190f721ab1912"
  },
  "json": null,
  "origin": "20.187.154.207",
  "url": "http://httpbin.org/put?user=foo"
}


OK

    Note:

    • The results you obtain may be different from those in the above response.

The DELETE method of HTTP client

In this example, the HTTP server is http://httpbin.org. The DELETE method is used to delete resources on a server. The exact use of DELETE requests depends on the server implementation.

  1. Restore factory default settings of the module.

    Command:

    AT+RESTORE

    Response:

    OK

  2. Set the Wi-Fi mode to station.

    Command:

    AT+CWMODE=1

    Response:

    OK

  3. Connect to the router.

    Command:

    AT+CWJAP="espressif","1234567890"

    Response:

    WIFI CONNECTED
WIFI GOT IP

OK

    Note:

    • The SSID and password you entered may be different from those in the above command. Please replace the SSID and password with those of your router settings.

  4. Send an HTTP DELETE request. Set opt to 5 (DELETE method), url to http://httpbin.org/delete, and transport_type to 1 (HTTP_TRANSPORT_OVER_TCP).

    Command:

    AT+HTTPCLIENT=5,0,"https://httpbin.org/delete",,,1

    Response:

    +HTTPCLIENT:282,{
  "args": {},
  "data": "",
  "files": {},
  "form": {},
  "headers": {
    "Content-Length": "0",
    "Content-Type": "application/x-www-form-urlencoded",
    "Host": "httpbin.org",
    "User-Agent": "ESP32 HTTP Client/1.0",
    "X-Amzn-Trace-Id": "Root=1-61504289-468a41
+HTTPCLIENT:114,737b0d251672acec9d"
  },
  "json": null,
  "origin": "20.187.154.207",
  "url": "https://httpbin.org/delete"
}


OK

    Note:

    • The results you obtain may be different from those in the above response.

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