

Response Flow Interceptor

Intercept the Response to the client and update headers, trailer and body before reaching the client.

Request and Response for Interceptor

In this section, you can find the content of the request to/response from the interceptor service.

1. Request from the Choreo Connect Router to Interceptor Service

Following is the request received from the Choreo Connect Router when you enable the response interceptor.

Format

{
    "requestHeaders": {
        "<header1_from_client>": "<value>",
        "<header2_from_client>": "<value>"
    },
    "requestTrailers": {
        "<trailer1_from_client>": "<value>",
        "<trailer2_from_client>": "<value>"
    },
    "requestBody": "<BASE64_encoded_client_request_body>",
    "responseCode": <response_code_from_backend>,
    "responseHeaders": {
        "<header1_from_backend>": "<value>",
        "<header2_from_backend>": "<value>"
    },
    "responseTrailers": {
        "<trailer1_from_backend>": "<value>",
        "<trailer2_from_backend>": "<value>"
    },
    "responseBody": "<BASE64_encoded_backend_response_body>",
    "interceptorContext": {
        "<key_1>": "<value_1>",
        "<key_2>": "<value_2>"
    },
    "invocationContext": {
        ...
    }
}

Sample

{
    "requestHeaders": {
        "content-type": "application/xml",
        "content-length": "40",
        "header1-from-client": "value1",
        "header2-from-client": "value2"
    },
    "requestTrailers": {
        "trailer1-from-client": "value1",
        "trailer2-from-client": "value2"
    },
    "requestBody": "PGhlbGxvPndvcmxkPC9oZWxsbz4K",
    "responseCode": 200,
    "responseHeaders": {
       "content-type": "application/xml",
       "content-length": "140"
   },
   "responseTrailers": {},
   "responseBody": "eyJIZWxsbyI6IldvcmxkIn0K44545487faedfasdfasdfasdfasdfasdadasdf",
   "interceptorContext": {
        "foo": "bar"
    },
    "invocationContext": {
        ...
    }
}

The requestHeaders, requestTrailers and requestBody fields in the above request to the interceptor service provide the request headers, trailers and base64 encoded request body from the client. The invocationContext contains additional request details. For more information, see Invocation Context. The interceptorContext contains key-value pairs that is set in request flow interceptorContext. For more information, see Interceptor Context.

The responseCode, responseHeaders, responseTrailers and responseBody fields in the request provides the response code, headers, trailers and base64 encoded response body from the backend.

You can customize the request body in the open API definition according to your requirements. For more information, see Defining Interceptors in an OpenAPI Definition.

2. Response from the Interceptor Service to Choreo Connect Router

The following is the response that interceptor service should respond to the Choreo Connect Router when you enable the response interceptor.

Format

{
    "responseCode": <HTTP_status_code>,
    "headersToAdd": {
        "<header_key_1>": "<value_1>",
        "<header_key_2>": "<value_2>"
    },
    "headersToRemove": [
        "<header_key_1>",
        "<header_key_2>"
    ],
    "headersToReplace": {
        "<header_key_1>": "<value_1>",
        "<header_key_2>": "<value_2>"
    },
    "trailersToAdd": {
        "<trailer_key_1>": "<value_1>",
        "<trailer_key_2>": "<value_2>"
    },
    "trailersToRemove": [
        "<trailer_key_1>",
        "<trailer_key_2>"
    ],
    "trailersToReplace": {
        "<trailer_key_1>": "<value_1>",
        "<trailer_key_2>": "<value_2>"
    },
    "body": "<BASE64_encoded_body>"
}

Sample

{
    "responseCode": 200,
    "headersToAdd": {
        "content-type": "application/json",
        "new-header": "value"
    },
    "headersToRemove": [
        "invalid-header"
    ],
    "headersToReplace": {
        "outdated-header": "updated value"
    },
    "trailersToAdd": {
        "new-trailer": "value"
    },
    "trailersToRemove": [
        "invalid-trailer"
    ],
    "trailersToReplace": {
        "outdated-trailer": "update value"
    },
    "body": "eyJIZWxsbyI6IldvcmxkIn0K"
}

Interceptor can instruct the Choreo-Connect Router what should be done with the above response.

Key in Response JSON	Description
responseCode	Sets the response code.
[headers|trailers]ToAdd	Appends a new value onto existing headers/trailers, or adds the headers/trailers if it does not already exist.
[headers|trailers]ToRemove	Deletes headers/trailers.
[headers|trailers]ToReplace	Sets the new value for existing headers/trailers, or adds the headers/trailers if it does not already exist.
body	Sets the body with base64 decoding the provided value. If the value is null (i.e. {"body": null}) or the key "body" is not defined (i.e. {}), body is not updated. If the value is empty (i.e. {"body": ""}), sets the body as empty.

Warning

If you update the response body before reaching the client, ensure to add response_body to the includes section of the Open API Specification. You may have a scenario like, whatever the response body from the backend, you define your own response body (say, based on a header value) to send to the client. Even though you do not read the response body, you should do the above inclusion.

Top