Hello, I want to download pdf from url using okhtt...

# announcements

[Vivek Modi]

Hello, I want to download pdf from url using okhttp with coroutine. I tried with simple but it's not working and also how to work with coroutine. Thanks

class FileDownloader {

    companion object {
        private const val BUFFER_LENGTH_BYTES = 1024 * 8
        private const val HTTP_TIMEOUT = 30
    }

    private var okHttpClient: OkHttpClient

    init {
        val okHttpBuilder = okHttpClient.newBuilder()
            .connectTimeout(HTTP_TIMEOUT.toLong(), TimeUnit.SECONDS)
            .readTimeout(HTTP_TIMEOUT.toLong(), TimeUnit.SECONDS)
        this.okHttpClient = okHttpBuilder.build()
    }

    fun download(url: String, file: File): {
            val request = Request.Builder().url(url).build()
            val response = okHttpClient.newCall(request).execute()
            val body = response.body
            val responseCode = response.code
            if (responseCode >= HttpURLConnection.HTTP_OK &&
                responseCode < HttpURLConnection.HTTP_MULT_CHOICE &&
                body != null) {
                val length = body.contentLength()
                body.byteStream().apply {
                    file.outputStream().use { fileOut ->
                        var bytesCopied = 0
                        val buffer = ByteArray(BUFFER_LENGTH_BYTES)
                        var bytes = read(buffer)
                        while (bytes >= 0) {
                            fileOut.write(buffer, 0, bytes)
                            bytesCopied += bytes
                            bytes = read(buffer)
                        }
                    }
                }
            } else {
                throw IllegalArgumentException("Error occurred when do http get $url")
            }
        }
    }
}

[knthmn]

What error are you getting?

As for coroutines, I have two points
• Instead of using Request.execute(), you can use Request.enqueue() to make it non blocking
• Make your download a suspend fun, and use ensureActive() or yield() in the transfer loop

[Vivek Modi]

how can i do Request.enqueue() is asking callback

[knthmn]

you can use suspendCancellableCoroutine() to convert it to a suspend function, remember to close the Response

[knthmn]

here is an implementation
https://github.com/gildor/kotlin-coroutines-okhttp/blob/master/src/main/kotlin/ru/gildor/coroutines/okhttp/CallAwait.kt