First cut of Google-http-client retrofitting

gistfile1.java

package uk.co.airsource.android.authtest;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import retrofit.client.Client;
import retrofit.client.Header;
import retrofit.client.Request;
import retrofit.client.Response;
import retrofit.mime.TypedInput;
import retrofit.mime.TypedOutput;

import com.google.api.client.auth.oauth2.ClientParametersAuthentication;

import com.google.api.client.http.AbstractHttpContent;
import com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpContent;
import com.google.api.client.http.HttpHeaders;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestFactory;

import com.google.api.client.http.HttpResponse;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;


/**
 * Created by sduke on 28/01/2015.
 */
public class GoogleHttpClient implements Client
{
    /** Global instance of the HTTP transport. */
    private static final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();
    //(use a nethttptransport)
    private final HttpRequestFactory requestFactory;
    //private final Credential.Builder credentialBuilder;

    //TODO: this goes into the authing http client.
    private final ClientParametersAuthentication clientParametersAuthentication;

    public GoogleHttpClient()//, Credential.Builder credentialBuilder)
    {
        super();
//        HTTP_TRANSPORT.createRequestFactory()
        this.requestFactory = HTTP_TRANSPORT.createRequestFactory( /*TODO: insert a request initializer here that checks for the credential*/);
        //this.credentialBuilder = credentialBuilder;
        clientParametersAuthentication = new ClientParametersAuthentication("api key", "api password");

        //this.credentialBuilder.setClientAuthentication(clientParametersAuthentication);
    }

    @Override
    public Response execute(final Request request) throws IOException
    {
        HttpRequest httpRequest = prepareRequest(request);
        httpRequest.setFollowRedirects(true);
        HttpResponse httpResponse = null;

        httpResponse = httpRequest.execute();

        return readResponse(httpResponse);
    }

    HttpRequest prepareRequest(Request request) throws IOException {
        TypedOutput body = request.getBody();
        HttpContent httpContent = null;
        if (body != null)
        {
            httpContent = new HttpContentStream(body);
        }

        HttpRequest httpRequest = requestFactory.buildRequest(
                request.getMethod(),
                new GenericUrl(request.getUrl()),
                httpContent
        );

        HttpHeaders httpRequestHeaders = httpRequest.getHeaders();

        for (Header header :request.getHeaders()) {
            httpRequestHeaders.set(header.getName(), header.getValue());
        }

        httpRequest.setHeaders(httpRequestHeaders);

        return httpRequest;
    }


    Response readResponse(HttpResponse httpResponse) throws IOException {
        int status = httpResponse.getStatusCode();
        String reason = httpResponse.getStatusMessage();
        if (reason == null) reason = "";

        List<Header> headers = new ArrayList<Header>();
        HttpHeaders httpResponseHeaders = httpResponse.getHeaders();
        for (String name : httpResponseHeaders.keySet())
        {
            for (String value : httpResponseHeaders.getHeaderStringValues(name))
            {
                headers.add(new Header(name, value));
            }
        }

        String mimeType = httpResponse.getContentType();
        Long lengthObj = httpResponseHeaders.getContentLength();
        long length = lengthObj != null ? lengthObj : -1;
        InputStream stream = httpResponse.getContent();
        TypedInput responseBody = new TypedInputStream(mimeType, length, stream);
        return new Response(httpResponse.getRequest().getUrl().build(), status, reason, headers, responseBody);
    }

//    public void doAuth()
//    {
//        //a temp method to hold some code for a bit
//        PasswordTokenRequest passwordTokenRequest = new PasswordTokenRequest(null, null, null, null, null);
//        TokenResponse tokenResponse = passwordTokenRequest.setClientAuthentication(clientParametersAuthentication).execute();
//        Credential credential = new Credential(BearerToken.authorizationHeaderAccessMethod()).setFromTokenResponse(tokenResponse);
//        //as per the
//    }

    private static class HttpContentStream extends AbstractHttpContent {
        private final TypedOutput output;

        private HttpContentStream(TypedOutput output) {
            super(output.mimeType());
            this.output = output;
        }

        @Override
        public void writeTo(OutputStream outputStream) throws IOException
        {
            output.writeTo(outputStream);
        }
    }

    private static class TypedInputStream implements TypedInput {
        private final String mimeType;
        private final long length;
        private final InputStream stream;

        private TypedInputStream(String mimeType, long length, InputStream stream) {
            this.mimeType = mimeType;
            this.length = length;
            this.stream = stream;
        }

        @Override public String mimeType() {
            return mimeType;
        }

        @Override public long length() {
            return length;
        }

        @Override public InputStream in() throws IOException {
            return stream;
        }
    }

}