Posted by Dan O’Meara, Program Manager, Google Cloud Platform team

We have invested heavily in our API and service infrastructure to improve performance and security and to add features developers need to build world-class APIs. As we make changes we must address features that are no longer compatible with the latest architecture and business requirements.

The JSON-RPC protocol (http://www.jsonrpc.org/specification) and Global HTTP Batch (Javascript example) are two such features. Our support for these features was based on an architecture using a single shared proxy to receive requests for all APIs. As we move towards a more distributed, high performance architecture where requests go directly to the appropriate API server we can no longer support these global endpoints.

As a result, next year, on January 25, 2019 we will discontinue support for both these features.

We know that these changes have customer impact and have worked to make the transition steps as clear as possible. Please see the guidance below which will help ease the transition.

What do you need to do?

Google API Client Libraries have been regenerated to no longer make requests to the global HTTP batch endpoint. Clients using these libraries must upgrade to the latest version. Clients not using the Google API Client Libraries and/or making custom calls to the JSON-RPC endpoint or HTTP batch endpoint will need to make the changes outlined below.

JSON-RPC

To identify whether you use JSON-RPC, you can check whether you send requests to https://www.googleapis.com/rpc or https://content.googleapis.com/rpc. If you do, you should migrate.

1. If you are using client libraries (either the Google published libraries or other libraries) that use the JSON-RPC endpoint, switch to client libraries that speak to the API's REST endpoint:

Example code for Javascript

Before

// json-rpc request for the list method
gapi.client.rpcRequest('zoo.animals.list', 'v2',
  name:'giraffe'}).execute(x=>console.log(x))

After

// json-rest request for the list method
gapi.client.zoo.animals.list({name:'giraffe'}).then(x=>console.log(x))

OR

1. If you are not using client libraries (i.e. making raw HTTP requests):
   1. Use the REST URLs, and
   2. Change how you form the request and parse the response.

Example code

Before

// Request URL (JSON-RPC)
POST https://content.googleapis.com/rpc?alt=json&key=xxx

// Request Body (JSON-RPC)
[{
  "jsonrpc":"2.0","id":"gapiRpc",
  "Method":"zoo.animals.list",
  "apiVersion":"v2",
  "Params":{"name":"giraffe"}
}]

After

// Request URL (JSON-REST)
GET https://content.googleapis.com/zoo/v2/animals?name=giraffe&key=xxx

HTTP batch

A batch request is homogenous if the inner requests are addressed to the same API, even if addressed to different methods of the same API. It is heterogeneous if the inner requests go to different APIs. Heterogeneous batching will not be supported after the turn down of the Global HTTP batch endpoint. Homogenous batching will still be supported but through API specific batch endpoints.

1. If you are currently forming heterogeneous batch requests:
   1. Change your client code to send only homogenous batch requests.

Example code

The example demonstrates how we can split a heterogeneous batch request for 2 apis (urlshortener and zoo) into 2 homogeneous batch requests.

Before

// heterogeneous batch request example.

// Notice that the outer batch request contains inner API requests
// for two different APIs.

// Request to urlshortener API
request1 = gapi.client.urlshortener.url.get({"shortUrl": "http://goo.gl/fbsS"});

// Request to zoo API
request2 = gapi.client.zoo.animals.list();

// Request to urlshortener API
request3 = gapi.client.urlshortener.url.get({"shortUrl": "https://goo.gl/XYFuPH"});

// Request to zoo API
request4 = gapi.client.zoo.animal.get("name": "giraffe");

// Creating single heterogeneous batch request object
heterogeneousBatchRequest = gapi.client.newBatch();
// adding the 4 batch requests
heterogeneousBatchRequest.add(request1);
heterogeneousBatchRequest.add(request2);  
heterogeneousBatchRequest.add(request3);
heterogeneousBatchRequest.add(request4);
// print the heterogeneous batch request
heterogeneousBatchRequest.then(x=>console.log(x));

After

// Split heterogeneous batch request into two homogenous batch requests

// Request to urlshortener API
request1 = gapi.client.urlshortener.url.get({"shortUrl": "http://goo.gl/fbsS"});

// Request to zoo API
request2 = gapi.client.zoo.animals.list();

// Request to urlshortener API
request3 = gapi.client.urlshortener.url.get({"shortUrl": "http://goo.gl/fbsS"})

// Request to zoo API
request4 = gapi.client.zoo.animals.list();
// Creating homogenous batch request object for urlshorterner
homogenousBatchUrlshortener = gapi.client.newBatch();

// Creating homogenous batch request object for zoo
homogenousBatchZoo = gapi.client.newBatch();
// adding the 2 batch requests for urlshorterner
homogenousBatchUrlshortener.add(request1); homogenousBatchUrlshortener.add(request3); 

// adding the 2 batch requests for zoo
homogenousBatchZoo.add(request2); 
homogenousBatchZoo.add(request4);
// print the 2 homogenous batch request
Promise.all([homogenousBatchUrlshortener,homogenousBatchZoo])
    .then(x=>console.log(x));

OR

2. If you are currently forming homogeneous batch requests
   1. And you are using Google API Client Libraries, then simply update to the latest versions.
   2. If you are using non-Google API client libraries or no client library (i.e making raw HTTP requests), then:
      • Change the endpoint from www.googleapis.com/batch to www.googleapis.com/batch//.
      • Or, simply read the value of 'batchPath' from the API's discovery doc and use that value.

For help on migration, consult the API documentation or tag Stack Overflow questions with the 'google-api' tag.