Echo Parameter
This mechanism is used in API design to associate requests and responses, especially when dealing with asynchronous operations.
Please see API Documentation here
Here's how it works:
1. Asynchronous Communication: Asynchronous communication is a method where a client (sender) initiates a request, and the server (receiver) processes the request separately. The server then responds to the client at a later time, typically after the request has been processed. This is useful when the processing time might be unpredictable or longer than immediate responses.
2. Request Format: When making a request to the server, you can include an additional parameter in the request body called "echo". The value of this parameter can be any data type, such as a string, integer, array, or object (map). This parameter serves as a marker that helps you identify the request and associate it with its corresponding response.
3. Example Request: For instance, if you send a request like this:
{
"url": "http://...",
"echo": "hello"
}
Here, you're requesting some operation to be performed at the URL "http://...". The "echo" parameter is set to "hello", which serves as a unique identifier for this particular request.
4. Processing on the Server: The server processes your request, performs the necessary operations (as specified by the URL), and at some point in the future, generates a response.
5. Response Format: When the server responds to your request, the response will contain the same "echo" parameter that you included in the original request. This allows you to associate the response with the initial request.
6. Example Response: Assuming the server responds with a result like this:
{
"result": {
// Other response data
"echo": "hello"
}
}
In this example, the "result.echo" field contains the same value ("hello") as the "echo" parameter in your original request. This enables you to correlate the response with the request that you made.
7. Benefits: This "echo" mechanism is particularly useful in scenarios where you make multiple asynchronous requests and must match each response to its corresponding request. You can easily link them by including a unique identifier (the "echo" parameter) in both the request and the response.
In summary, the "echo" parameter is a tagging mechanism that helps you keep track of asynchronous requests and their corresponding responses. It's a way to maintain context and ensure that you can associate each response with the specific request that triggered it.