Handling POST requests with Android Annotations

Question

I am trying to consume a RESTful API using AA. My API receives email and password request parameters (not JSON!) and returns an APIKey (which I use Jackson2 to deserialize).

Ideally, I want to use a regular old Map<String, String> to send the email and password, but it appears AA requires me to use a MultiValueMap (which is a Map<K,List<V>>), or a custom class (Event, which has no source shown).

When using a MultiValueMap, an array is sent. I am not sending an array of email and passwords, I am sending a single email and password:

// LoginFragment.java            
MultiValueMap<String, String> credentials = new LinkedMultiValueMap<String, String>();
credentials.add("email", email);
credentials.add("password", password);
APIKey resp = userRest.login(credentials);


// UserRest.java
@Post("user/login")
public APIKey login(MultiValueMap credentials);

Which trips up my API, because it expects a String rather than an array of Strings.

So I'm thinking I have to create a custom Credentials object to hold my email and password, and somehow get it serialized to be sent to the server. Could someone help me out with this?

riggaroo · Accepted Answer · 2014-05-22T09:38:31.533

Have you not looked at using the built in Authentication mechanisms that Android Annotations provides? Like Basic Auth or OAuth? This might be a cleaner solution.

https://github.com/excilys/androidannotations/wiki/Authenticated-Rest-Client

I have used the Basic Auth options - https://github.com/excilys/androidannotations/wiki/Rest%20API

You just need to add a method to your interface:

void setHttpBasicAuth(String username, String password);

Then call that before making the API call. There should be a similar option for OAuth.

EDIT: You can create a Login POJO to POST to your API:

@JsonInclude(JsonInclude.Include.NON_NULL)
@Generated("org.jsonschema2pojo")
@JsonPropertyOrder({
        "name",
        "password"

})
public class Login{
    @JsonProperty("name")
    private String name;
    @JsonProperty("password")
    private String password;

}

and then in your API Interface you can do the following:

  @Post("user/login")
    public APIKey login(Login credentials);

This will then POST your data to the /user/login method. You might need to add an interceptor depending on what kind of data you wish to parse ie converters = { MappingJacksonHttpMessageConverter.class } etc.

This API does not support Basic Auth, and login() is a POST request, so appending to the URL shouldn't solve my problem (I'm not sure if that's so secure either). I did in fact use the interceptor pattern from that page for injecting the necessary API Key for all requests. However, my question was regarding sending POST data with Android Annotations, not authentication. I'm specifically looking for a way (maybe a POJO?) to send the email and password via POST (ie: email=me@example.com, password=example). The Event class they use in the examples is nowhere to be found. — Marco Pietro Cirillo, May 21 '14 at 18:30

score 1 · Answer 2 · answered Jun 05 '14 at 00:33

I know you already figured it out but check out the rest interceptor I use. Basically it attaches an api_key,access_token, and a hmac_sig to each request in the headers. Then you can validate the credientials server side

@EBean(scope = Scope.Singleton)
public class RestInterceptor implements ClientHttpRequestInterceptor {

private int requestCount = 0;

@Pref
MyPrefs_ myPrefs;

private RequestListener mRequestListener;

public interface RequestListener {
    void report(int count);
}

public void setOnRequestListener(RequestListener requestListener) {
    this.mRequestListener = requestListener;
}

public ClientHttpResponse intercept(HttpRequest request, byte[] data, ClientHttpRequestExecution execution)
        throws IOException {

    if (mRequestListener != null) {
        requestCount++;
        mRequestListener.report(requestCount);
    }

    HttpHeaders headers = request.getHeaders();

    long unixTime = System.currentTimeMillis() / 1000L;

    headers.add("request_time", String.valueOf(unixTime));

    if (myPrefs.accessToken().exists()) {

        headers.add("access_token", myPrefs.accessToken().get());


        String hmacInput; //left this part out but basically do something unique to the request here and do the same on the other side.

        String hmacKey = myPrefs.accessToken().getOr("");


        try {
            String hmacSig = hmacSha1(hmacInput, hmacKey);

            headers.add("hmac_sig", hmacSig);

        }
        catch (InvalidKeyException e) {

            e.printStackTrace();
        }
        catch (NoSuchAlgorithmException e) {

            e.printStackTrace();
        }


    }
    if (myPrefs.userId().exists()) {
        headers.add("user_id", String.valueOf(myPrefs.userId().get()));
    }

    headers.add("api_key", "somerandomstring");

    ClientHttpResponse t = execution.execute(request, data);

    if (mRequestListener != null) {

        requestCount--;
        mRequestListener.report(requestCount);
    }

    return t;
}


public void resetRequestCount() {
    this.requestCount = 0;
}

public static String hmacSha1(String value, String key) throws UnsupportedEncodingException,
        NoSuchAlgorithmException, InvalidKeyException {
    String type = "HmacSHA1";
    SecretKeySpec secret = new SecretKeySpec(key.getBytes(), type);
    Mac mac = Mac.getInstance(type);
    mac.init(secret);
    byte[] bytes = mac.doFinal(value.getBytes());
    return bytesToHex(bytes);
}

private final static char[] hexArray = "0123456789abcdef".toCharArray();

private static String bytesToHex(byte[] bytes) {
    char[] hexChars = new char[bytes.length * 2];
    int v;
    for (int j = 0; j < bytes.length; j++) {
        v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
}

}

Handling POST requests with Android Annotations

2 Answers2