Building an Android QUIC REST Client with HQUIC [kotlin] - Huawei Developers

In a previous post I've shown you how to use the HQUIC kit to perform a simple GET request to download the latest local news by using a third party API. At this point everything is ok, but, what if I want to send a request with headers? or, how can I perform a POST request?. If you have made the same questions, please keep reading.
Previous requirements
An Android Studio project
Integrating the HQUIC SDK
HQUC will perform HTTP requests over the QUIC protocol to let your users enjoy faster connections with lower bandwidth. If the remote server does not support QUIC, the kit will use HTTP V2 instead, so, you just need to code once.
To add the HQUIC kit to your app, add the next dependency to your app level build.gradle file
Code:
implementation 'com.huawei.hms:hquic-provider:5.0.0.300'
Sync your project and you will be ready to use the HQUIC SDK. We will reuse the HQUICService class provided on the HQUIC sample code, but with little modifications
Code:
class HQUICService(val context: Context) {
private val TAG = "HQUICService"
private val DEFAULT_PORT = 443
private val DEFAULT_ALTERNATEPORT = 443
private val executor: Executor = Executors.newSingleThreadExecutor()
private var cronetEngine: CronetEngine? = null
private var callback: UrlRequest.Callback? = null
/**
* Asynchronous initialization.
*/
init {
HQUICManager.asyncInit(
context,
object : HQUICManager.HQUICInitCallback {
override fun onSuccess() {
Log.i(TAG, "HQUICManager asyncInit success")
}
override fun onFail(e: Exception?) {
Log.w(TAG, "HQUICManager asyncInit fail")
}
})
}
/**
* Create a Cronet engine.
*
* @param url URL.
* @return cronetEngine Cronet engine.
*/
private fun createCronetEngine(url: String): CronetEngine? {
if (cronetEngine != null) {
return cronetEngine
}
val builder = CronetEngine.Builder(context)
builder.enableQuic(true)
builder.addQuicHint(getHost(url), DEFAULT_PORT, DEFAULT_ALTERNATEPORT)
cronetEngine = builder.build()
return cronetEngine
}
/**
* Construct a request
*
* @param url Request URL.
* @param method method Method type.
* @return UrlRequest urlrequest instance.
*/
private fun builRequest(
url: String,
method: String,
headers: HashMap<String, String>?,
body:ByteArray?
): UrlRequest? {
val cronetEngine: CronetEngine? = createCronetEngine(url)
val requestBuilder = cronetEngine?.newUrlRequestBuilder(url, callback, executor)
requestBuilder?.apply {
setHttpMethod(method)
if(method=="POST"){
body?.let {
setUploadDataProvider(UploadDataProviders.create(ByteBuffer.wrap(it)), executor) }
}
headers?.let{
for (key in it.keys) {
addHeader(key, headers[key])
}
}
return build()
}
return null
}
/**
* Send a request to the URL.
*
* @param url Request URL.
* @param method Request method type.
*/
fun sendRequest(url: String, method: String, headers: HashMap<String, String>?=null,body:ByteArray?=null) {
Log.i(TAG, "callURL: url is " + url + "and method is " + method)
val urlRequest: UrlRequest? = builRequest(url, method, headers,body)
urlRequest?.apply { urlRequest.start() }
}
/**
* Parse the domain name to obtain the host name.
*
* @param url Request URL.
* @return host Host name.
*/
private fun getHost(url: String): String? {
var host: String? = null
try {
val url1 = URL(url)
host = url1.host
} catch (e: MalformedURLException) {
Log.e(TAG, "getHost: ", e)
}
return host
}
fun setCallback(mCallback: UrlRequest.Callback?) {
callback = mCallback
}
}
The sendRequest method has been modified to receive a HashMap with the headers, and a ByteArray with the Body payload. Note the sendRequest method if the body or the headers are not null, will be added to the request.
Code:
requestBuilder?.apply {
setHttpMethod(method)
if(method=="POST"){
body?.let {//Adding the request Body
setUploadDataProvider(UploadDataProviders.create(ByteBuffer.wrap(it)), executor) }
}
headers?.let{
for (key in it.keys) {//Adding all the headers
addHeader(key, headers[key])
}
}
With that modifications can perform an HTTP request by this way
Code:
val map=HashMap<String,String>()
map["Content-Type"] = "application/json"
val body=JSONObject().apply {
put("key1","value1")
put("key2","value2")
}
HQUICService(context).sendRequest(HOST,"POST",map,body.toString().toByteArray())
That's enough to send a request, but, what about the response? HQUIC provides an Abstract Class for listening the request events. All we need is inherit from UrlRequest.Callback. Let's do it.
Code:
class HQUICClient(context: Context) : UrlRequest.Callback() {
var hquicService: HQUICService? = null
val CAPACITY = 10240
val TAG="QUICClient"
val response=ByteArrayOutputStream()
var listener:QuicClientListener?=null
init {
hquicService = HQUICService(context)
hquicService?.setCallback(this)
}
fun makeRequest(url: String, method: String, headers: HashMap<String, String>?=null,body:ByteArray?=null){
hquicService?.sendRequest(url,method,headers,body)
}
override fun onRedirectReceived(
request: UrlRequest?,
info: UrlResponseInfo?,
newLocationUrl: String?
) {
request?.followRedirect()
}
override fun onResponseStarted(request: UrlRequest?, info: UrlResponseInfo?) {
val byteBuffer = ByteBuffer.allocateDirect(CAPACITY)
request?.read(byteBuffer)
}
override fun onReadCompleted(
request: UrlRequest?,
info: UrlResponseInfo?,
byteBuffer: ByteBuffer?
) {
byteBuffer?.apply {
response.write(array(),arrayOffset(),position())
response.flush()
}
request?.read(ByteBuffer.allocateDirect(CAPACITY))
}
override fun onSucceeded(request: UrlRequest?, info: UrlResponseInfo?) {
listener?.onSuccess(response.toByteArray())
}
override fun onFailed(request: UrlRequest?, info: UrlResponseInfo?, error: CronetException?) {
listener?.apply { onFailure(error.toString()) }
}
Remember, certain number of bytes can be readed per time, so for long responses, the method onReadCompleated will be called multiple times until the response has been successfully readed, or an error ocurs. When the operation is complete, the onSucceeded callback will be called and you will be able to parse the response. If the request fails, you will get an exception on the onFailed callback.
To report the request result, you can create a public interface
Code:
interface HQUICClientListener{
fun onSuccess(response: ByteArray)
fun onFailure(error: String)
}
And then, if the response is succesful, you can parse your byte array properly.
Code:
override fun onSuccess(response: ByteArray) {
//For text
Log.i(TAG, String(response))
//For images
BitmapFactory.decodeByteArray(response,0,response.size)
}
Conclusion
With HQUIC you can easily create a REST client for your android app, taking advantage of the QUIC features and keeping HTTP 2 compatibility.
Reference
HQUIC developer guide