When your application requests private data, the request must be authorized by an authenticated user who has access to that data.
When your application requests public data, the request doesn't need to be authorized, but does need to be accompanied by an identifier, such as an API key.
Every request your application sends to the Google Cloud Storage JSON API needs to identify your application to Google. There are two ways to identify your application: using an OAuth 2.0 token (which also authorizes the request) and/or using the application's API key. Here's how to determine which of those options to use:
- If the request requires authorization (such as a request for an individual's private data), then the application must provide an OAuth 2.0 token with the request. The application may also provide the API key, but it doesn't have to.
- If the request doesn't require authorization (such as a request for public data), then the application must provide either the API key or an OAuth 2.0 token, or both—whatever option is most convenient for you.
About authorization protocols
Authorizing requests with OAuth 2.0
Requests to the Google Cloud Storage JSON API for non-public user data must be authorized by an authenticated user.
The details of the authorization process, or "flow," for OAuth 2.0 vary somewhat depending on what kind of application you're writing. The following general process applies to all application types:
- When you create your application, you register it using the Google Developers Console. Google then provides information you'll need later, such as a client ID and a client secret.
- Activate the Google Cloud Storage JSON API in the Google Developers Console. (If the API isn't listed in the Developers Console, then skip this step.)
- When your application needs access to user data, it asks Google for a particular scope of access.
- Google displays a consent screen to the user, asking them to authorize your application to request some of their data.
- If the user approves, then Google gives your application a short-lived access token.
- Your application requests user data, attaching the access token to the request.
- If Google determines that your request and the token are valid, it returns the requested data.
Some flows include additional steps, such as using refresh tokens to acquire new access tokens. For detailed information about flows for various types of applications, see Google's OAuth 2.0 documentation.
Here's the OAuth 2.0 scope information for the Google Cloud Storage JSON API:
||Read/write and ACL management access to Google Cloud Storage.|
||Read/write access to Google Cloud Storage.|
||Read-only access to Google Cloud Storage.|
To request access using OAuth 2.0, your application needs the scope information, as well as information that Google supplies when you register your application (such as the client ID and the client secret).
Acquiring and using an API key
To acquire an API key:
- Go to the Google Developers Console.
- Select a project, or create a new one.
- In the sidebar on the left, expand APIs & auth. Next, click APIs. Select the Enabled APIs link in the API section to see a list of all your enabled APIs. Make sure that the Google Cloud Storage JSON API is on the list of enabled APIs. If you have not enabled it, select the API from the list of APIs, then select the Enable API button for the API.
- In the sidebar on the left, select Credentials.
This API supports two types of credentials.
Create whichever credentials are appropriate for your project:
OAuth: Your application must send an OAuth 2.0 token with any request that accesses private user data. Your application sends a client ID and, possibly, a client secret to obtain a token. You can generate OAuth 2.0 credentials for web applications, service accounts, or installed applications.
To create an OAuth 2.0 token, click Create new Client ID, provide the required information where requested, and click Create Client ID.
Public API access: A request that does not provide an OAuth 2.0 token must send an API key. The key identifies your project and provides API access, quota, and reports.
To create an API key, click Create new Key and select the appropriate key type. Enter the additional information required for that key type and click Create.
To keep your API keys secure, follow the best practices for securely using API keys.
After you have an API key, your application can append the query parameter
key=yourAPIKey to all request URLs.
The API key is safe for embedding in URLs; it doesn't need any encoding.