Overriding API request with Retrofit

Rishabh Sharma

1 February 2021

In the mobile app development lifecycle, communicating with the server(via API) to get or store data is one of the basic needs.

Retrofit is a type-safe REST client for Android, Java and Kotlin developed by Square. The library provides a powerful framework for authenticating and interacting with APIs and sending network requests. I am writing this blog is written to express a special case while using Retrofit.

Let’s understand the use case with an example.

Suppose we need to override our API requests to add a key in every API of our project then we need to edit all our API requests or we can edit our client to add a key in all requests. We can do it by overriding our requests.

Below is the code example:

Request request = chain.request();
Request.Builder builder = request.newBuilder();
if (request.method().equals("GET") || request.method().equals("PUT")) {
    HttpUrl originalHttpUrl = request.url();
    HttpUrl url = originalHttpUrl.newBuilder()
            .addQueryParameter("lending_id", "disable")   // Request customization: add request headers
            .build();
    
    builder.url(url);
} else {
    if ("POST".equals(request.method())) {
        if (request.body() instanceof FormBody) {
            FormBody.Builder bodyBuilder = new FormBody.Builder();
            FormBody formBody = (FormBody) request.body();
            // Copy the original parameters first
            for (int i = 0; i < formBody.size(); i++) {
                bodyBuilder.addEncoded(formBody.encodedName(i), formBody.encodedValue(i));
            }
            // Add common parameters
            formBody = bodyBuilder
                    .addEncoded("lending_id", "disable")
                    .build();
            builder.post(formBody).build();
        }
    }
}
builder.addHeader("Content-Type", "text/html")
       .addHeader("authKey", ApplicationSingleton.getInstance().getAuthKey());

Request request = chain.request();

Request.Builder builder = request.newBuilder();

if (request.method().equals("GET") || request.method().equals("PUT")) {

HttpUrl originalHttpUrl = request.url();

HttpUrl url = originalHttpUrl.newBuilder()

.addQueryParameter("lending_id", "disable") // Request customization: add request headers

.build();

builder.url(url);

} else {

if ("POST".equals(request.method())) {

if (request.body() instanceof FormBody) {

FormBody.Builder bodyBuilder = new FormBody.Builder();

FormBody formBody = (FormBody) request.body();

// Copy the original parameters first

for (int i = 0; i < formBody.size(); i++) {

bodyBuilder.addEncoded(formBody.encodedName(i), formBody.encodedValue(i));

}

// Add common parameters

formBody = bodyBuilder

.addEncoded("lending_id", "disable")

.build();

builder.post(formBody).build();

}

builder.addHeader("Content-Type", "text/html")

.addHeader("authKey", ApplicationSingleton.getInstance().getAuthKey());

In conclusion, in this way we can override our requests with Retrofit.

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