Before you can start coding your first client application, there are a few things you need to do, if you haven't done them already.
Get a Google Account
You may also want a separate Google Account for testing purposes.
Create a project for your client
Before you can send requests to Google Knowledge Graph Search API, you need to tell Google about your client and activate access to the API. You do this by using the Google Developers Console to create a project, which is a named collection of settings and API access information, and register your application.
To get started using Google Knowledge Graph Search API, you need to first create or select a project in the Google Developers Console and enable the API. Using this link guides you through the process and activates the Google Knowledge Graph Search API automatically.
Alternatively, you can activate the Google Knowledge Graph Search API yourself in the Developers Console by doing the following:
- Open the Credentials page.
In either case, you end up on the Credentials page and can create your project's credentials from here.
If you haven't done so already, create your application's API key by clicking Add credentials > API key. Next, look for your API key in the API keys section.
Learn REST basics
There are two ways to invoke the API:
- Sending HTTP requests and parsing the responses.
- Using client libraries.
If you decide not to use client libraries, you'll need to understand the basics of REST.
REST is a style of software architecture that provides a convenient and consistent approach to requesting and modifying data.
The term REST is short for "Representational State Transfer." In the context of Google APIs, it refers to using HTTP verbs to retrieve and modify representations of data stored by Google.
In a RESTful system, resources are stored in a data store; a client sends a request that the server perform a particular action (such as creating, retrieving, updating, or deleting a resource), and the server performs the action and sends a response, often in the form of a representation of the specified resource.
In Google's RESTful APIs, the client specifies an action using an HTTP verb such as
DELETE. It specifies a resource by a globally-unique URI of the following form:
Because all API resources have unique HTTP-accessible URIs, REST enables data caching and is optimized to work with the web's distributed infrastructure.
For more information about REST, you may find the following third-party documents useful:
- Building Web Services the REST Way, which is aimed at service providers but provides a good overview of REST
- HTTP 1.1 method definitions; specification for
REST in the Google Knowledge Graph Search API
The Google Knowledge Graph Search API operations map directly to REST HTTP verbs.
The specific formats for Google Knowledge Graph Search API URIs are:
The full set of URIs used for each supported operation in the API is summarized in the Google Knowledge Graph Search API Reference document.
Learn JSON basics
The Google Knowledge Graph Search API returns data in JSON format.