Google APIs

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I have been thinking what I should write about for a while. Believe it or not, even though I have two weeks off from work during this holiday season, I still want to do what I do at work – building applications. This blog post is about Google APIs, specifically the Books API with which I built a simple book search application. While there are a lot of APIs available out there, Google APIs is pretty cool to try out.

Currently, there are 55 available APIs on Google APIs Console including Analytics API, Drive API, and YouTube Analytics API. Most APIs have request limits for free usage but some of them are available only with pricing plan such as Google Cloud SQL and Google Maps Geolocation API. The usage of API access is tracked by the API key generated on the website and you can view the quotas and report as well.

Google Books API allows you to perform CRUD operations on Google Books database with the proper authorization. The search scope can be the whole database or specific users’ both custom and pre-defined bookshelves like books they marked as favorites or read. Operations to retrieve user private data require OAuth token which can be easily generated on the Google API access page. The book concepts are easy to understand except that a book is given a term “volume” in the API.

For the coding part, you will need to request a script from Google API website.

//load script to access Google API
<script src="https://apis.google.com/js/client.js?onload=onLoadCallback"> </script>

Once the script is loaded, you can configure the client object for the query request that you are making.

function onLoadCallback(){
   var _this = this;
   //in this example, the param for API is "books" and the param for API version is 'v1' 
   this.client.load('books', 'v1', function (data) {
      //specify your API key       
      _this.client.setApiKey("{Your API key}");
   });
}

Now you can send any search requests with different parameters. The parameter “fields” defines the data fields to be returned. It’s important because without it, a large object with the complete information of books will be returned. You will never need so much information for your application and it would decrease the performance significantly.

var params = {
          //fields to return. return full information by default.
          fields:"items(volumeInfo/title, volumeInfo/authors,volumeInfo/publishedDate, 
                  volumeInfo/description, volumeInfo/imageLinks/thumbnail)",
          //maximum number of results to return. 10 by default
          maxResults:15,
          //sorting method. "relevance" by default
          orderBy:"newest"
    },
    restRequest = this.client.request({
          //specify the query request. 
          //the path below will return maximum number of 15 books 
          //with information matching "javascript" ordered by the most recent published date
          path:"/books/v1/volumes?q=javascript" + "&fields=" + params.fields 
               + "&maxResults=" + params.maxResults + "&orderBy=" + params.orderBy
    });

//sent the request
restRequest.execute(function (resp) {
   //use the return data 
});

With the proper data, you can build so many amazing applications. Google Books API is one of the easy-to-use APIs that I have used but there are a lot more features that I want to add to my Book Search with Google Books API application. If I ever run out of ideas for blogging, that’s what I am going to do :)


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