HTTP Client
Add-On Required: This feature requires the Simulink Support Package for Raspberry Pi Hardware add-on.
Libraries:
Simulink Support Package for Raspberry Pi Hardware /
Network
Description
Use the HTTP Client block to send and receive data from the remote server using the HTTP protocol. You can send data in the text or JSON formats. The Raspberry Pi® hardware acts as a client and can send HTTP requests to the remote server over a uniform resource locator (URL) connection. The block supports the HTTP GET, POST, and PUT methods.
Ports
Input
URL — URL of server
character vector
Specify the URL of the server at this port as a uint8
vector input.
Tip
If you are using the String
library blocks to create a URL, use a String to
ASCII block to convert the string to a uint8
vector.
Data Types: uint8
Payload — Request payload
character vector
Specify at this port the data that you want the Raspberry Pi hardware to send as part of an HTTP request to the remote server.
Dependencies
To enable this port, select Request has payload input.
Data Types: uint8
Output
Status — Status of HTTP request
0
| 1
| 2
This port outputs the status of the HTTP request to the remote server.
0
— Indicates a failure in sending the request to the server.1
— Indicates that the Raspberry Pi hardware successfully sent the request to the server.2
— Indicates an invalid request. The block waits to make the next HTTP request to the server.
Data Types: uint8
Error — Error message from server
character vector
This port outputs the error message from the server related to all communication
failures. If the Status port outputs 0
or
2
, then the Error port outputs the
corresponding error message.
Dependencies
To enable this port, clear Request has response output.
Data Types: uint8
Response — Response message from server
character vector
This port outputs the response message from the server related to all successful
HTTP requests. If the Status port outputs 0
,
then the Error port outputs the error message. If the
Status port outputs 1
, then the
Response port outputs the response message.
Dependencies
To enable this port, select Request has response output.
Data Types: uint8
Data Size — Size of response data from server
scalar
This port outputs the size of the response message data received from the server.
Dependencies
To enable this port, select Request has response output.
Data Types: int32
Parameters
Main
Request Method — HTTP request method
GET
(default) | POST
| PUT
Select the HTTP request method.
GET
— This method requests data from a specified resource.POST
— This method sends data to a server to create a resource.PUT
— This method sends data to a server to update a resource.
Update Interval (seconds) — Interval between HTTP requests
2
(default) | positive integer
Specify the number of seconds to wait between subsequent HTTP requests.
Request has payload input — Payload input in request
off
(default) | on
Select this option if the HTTP request contains payload data in the JSON or text formats.
Content Type — Input payload content type
application/json
(default) | text/plain
Select the content type of the payload input in the HTTP request. If you select the POST or PUT request methods, the client sends the content type information to the server directly based on the data.
Dependencies
To enable this parameter, select Request has payload input.
Request has response output — Payload output in response
off
(default) | on
Select this option if the HTTP response from the server contains payload data.
Maximum length of the output Message — Maximum length of output data
256
(default) | positive integer
Enter the maximum length of the expected payload data.
Dependencies
To enable this parameter, select Request has response output.
Accept — Format of output data
application/json
(default) | text/plain
Select the format of the output payload data.
Dependencies
To enable this parameter, select Request has response output.
Print diagnostic messages — Print diagnostic messages on serial port
off
(default) | on
Select this option to print diagnostic messages for each HTTP request on the Raspberry Pi serial port.
Advanced
Number of custom headers — HTTP request headers
0
(default) | 1
| 2
| 3
Select the number of custom HTTP request headers. You can customize a header that
contains one or more key-value pairs to provide more information about the request.
The value 0
indicates that the HTTP request has no custom header.
Similarly, the value 2
indicates that the HTTP request has two
custom headers.
Key — HTTP request header key
character vector
Specify the key of the HTTP request header. The number of Key
parameter boxes in the block dialog box depends on the number of headers you specify
in the Number of custom headers parameter. For example, if you
set Number of custom headers to 2
, the
block generates two Key parameters.
Dependencies
To enable this parameter, set Number of custom headers to
1
,2
, or3
.
Value — HTTP request header value
character vector
Specify the value of the custom HTTP request header key. The number of
Value parameter boxes in the block dialog box depends on the
number of headers you specify in the Number of custom headers
parameter. For example, if you set Number of custom headers to
3
, the block generates three Value
parameters.
Dependencies
To enable this parameter, set Number of custom headers to
1
,2
, or3
.
Version History
Introduced in R2023b
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