openhab-docs/configuration/blockly/rules-blockly-http.md

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documentation	Rules Blockly - Logging

HTTP

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Introduction

This section explains the blocks that allow sending HTTP requests.

HTTP Requests

There is one block that handles all type of requests. Depending on the required functionality it changes its design.

Option Toggles

There are three toggle buttons that allow the block to be small for simple requests and add further options to be used:

• Clock: enables the timeout option
• H: enables the header option and allows to provide headers during the request via a Dictionary
• Q: enables the query option and allows to provide URI query parameters during the request via a Dictionary, the query parameters will be URI encoded

Query Parameters are used to provide additional information to the server, for example, to filter results or specify options for the request. These are typically provided in the URI as key-value pairs, like ?key1=value1&key2=value2. Instead of manually constructing the URI with query parameters, you can use the query option to provide a Dictionary of query parameters, which will be automatically URI encoded.

HTTP Request GET

Function: Send an HTTP GET request to a server and receive the response

The simplest form is shown by default and accepts the destination URI as String, e.g., GET http://openhab.org. See below for an example of a GET request with query parameters (likehttp://example.com/api?param1=value1&param2=value2`).

By activating the toggles the timeout, request headers and query parameters can be provided. Instead of creating a URI containing the query parameters, you can use the query parameter option and provide a Dictionary of query parameters. The provided parameters will automatically be URI encoded.

Here is an example also using a query parameter.

Another example shows how several query parameters can be provided using a Dictionary:

If you want to send a request with parameters like http://example.com/api?param1=value1&param2=value2, the request can be constructed as follows:

• URI: http://example.com/api with two query parameters param1 and param2
  • where param1 has a value that contains special characters, like EncodedValueWithSpecialCharacters->!
  • and param2 has a value of value2

you can use the following block:

which results in the following request:

http://example.com/api?param1=EncodedValueWithSpecialCharacters-%3E!&param2=value2

See the POST-Request below for an example showing the use additional fields.

HTTP Request POST

Function: Send an HTTP POST request to a server and receive the response

The simplest form is shown by default and accepts the destination URI as String and in comparison to the GET-Request adds a section for the payload which takes two parameters:

• the MIME-type of the content to be sent
• the content to be sent to the destination

For MIME-type application/json you can provide an object as content, and it will be converted to a JSON string. For application/x-www-form-urlencoded, you can provide a Dictionary and it will be URI encoded.

Here is a more complex example that additionally sets a header and a timeout:

HTTP Request PUT

Function: Send an HTTP PUT request to a server and receive the response

The simplest form is shown by default and accepts the destination URI as String and is similar in functionality to the POST-Request:

• the MIME-type of the content to be sent
• the content to be sent to the destination

Notice the construction of an object with a Dictionary also containing a List for the JSON payload.

HTTP Request DELETE

Function: Send an HTTP DELETE request to a server and receive the response

The simplest form is shown by default and accepts the destination URI as String.

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