Doing HTTP request in Scala

Question

I am trying to issue a simple POST request to a webservice which returns some XML in Scala.

It seems that Dispatch is the standard library used for this task, but I

Answer 1

Another option is Typesafe's play-ws, which is the Play Framework WS library broken out as a standalone lib:

http://blog.devalias.net/post/89810672067/play-framework-seperated-ws-library

I wouldn't necessarily offer this as the best option, but worth mentioning.

Answer 2

Here is a class I was working on. It has both GET and POST requests. GET without parameters - POST with parameters I used it to communicate with StreamSets in order to start a pipeline or check a pipeline status.

it only need the following dependency in the build.sbt file:

libraryDependencies += "org.scalaj" %% "scalaj-http" % "2.3.0"

You can find the documentation here: https://github.com/scalaj/scalaj-http#post-raw-arraybyte-or-string-data-and-get-response-code

import scala.collection.mutable.ArrayBuffer
import scalaj.http.{Http, HttpResponse}

object HttpRequestHandler {

  val userName: String = "admin"
  val password: String = "admin"

  def sendHttpGetRequest(request: String): String = {

    println(" Send Http Get Request (Start) ")

    try {

      val httpResponse: HttpResponse[String] = Http(request).auth(userName,password)
                                                            .asString

      val response = if (httpResponse.code == 200) httpResponse.body
      else{
        println("Bad HTTP response: code = "+httpResponse.code )
        return "ERROR"
      }

      println(" Send Http Get Request (End) ")

      return response

    } catch {
      case e: Exception => println("Error in sending Get request: "+e.getMessage)
        return "ERROR"
    }


  }

  def arrayBufferToJson(params:ArrayBuffer[(String,String)]): String ={

    var jsonString = "{"
    var count: Int = 0
    for(param <- params){
      jsonString+="\""+param._1+"\":\""+param._2+"\""+ ( if(count!=params.length-1) "," else "")
      count+=1
    }
    jsonString+="}"

    return jsonString

  }

  def sendHttpPostRequest(request: String,params: ArrayBuffer[(String,String)]): String = {

    println(" Send Http Post Request (Start) ")

    try {
      val postData : String = arrayBufferToJson(params)
      println("Parameters: "+postData)
      val httpResponse: HttpResponse[String] = Http(request).auth(userName,password)
                                                            .header("X-Requested-By","sdc")
                                                            .header("Content-Type", "application/json;charset=UTF-8")
                                                            .header("X-Stream" , "true")
                                                            .header("Accept", "application/json")
                                                            .postData(postData.getBytes)
                                                            .asString


      val response = if (httpResponse.code == 200) httpResponse.body
      else{
        println("Bad HTTP response: code = "+httpResponse.code )
        "ERROR"
      }

      println(" Send Http Post Request (End) ")

      return response

    } catch {
      case e: Exception => println("Error in sending Post request: " + e.getMessage)
        return "ERROR"
    }
  }

}

Answer 3

I use the following: https://github.com/scalaj/scalaj-http.

Here's a simple GET request:

import scalaj.http.{Http, HttpOptions}

Http("http://example.com/search").param("q", "monkeys").asString

and an example of a POST:

val result = Http("http://example.com/url").postData("""{"id":"12","json":"data"}""")
  .header("Content-Type", "application/json")
  .header("Charset", "UTF-8")
  .option(HttpOptions.readTimeout(10000)).asString

Scalaj HTTP is available through SBT:

libraryDependencies += "org.scalaj" % "scalaj-http_2.11" % "2.3.0"