As of April 2022 there are many supported options for making HTTP calls in scala:

• sttp or http4s might be good scala first options
• The native HttpClient library if you're using JDK 11+ and want minimal deps

If you've inherited a codebase that's using this library, I would suggest just copying the source code (it's only four files, and no depedencies) and make whatever fixes/changes you want.

Good luck!

This is a fully featured http client for Scala which wraps java.net.HttpURLConnection

Features:

• Zero dependencies
• Cross compiled for Scala 2.10, 2.11, 2.12, and 2.13-M3
• OAuth v1 request signing
• Automatic support of gzip and deflate encodings from server
• Easy to add querystring or form params. URL encoding is handled for you.
• Multipart file uploads

Non-Features:

• Async execution
  • The library is thread safe. HttpRequest and HttpResponse are immutable. So it should be easy to wrap in an execution framework of your choice.

Works in Google AppEngine and Android environments.

Big differences:

• Executing the request always returns a HttpResponse[T] instance that contains the response-code, headers, and body
• Exceptions are no longer thrown for 4xx and 5xx response codes. Yay!
• Http(url) is the starting point for every type of request (post, get, multi, etc)
• You can easily create your own singleton instance to set your own defaults (timeouts, proxies, etc)
• Sends "Accept-Encoding: gzip,deflate" request header and decompresses based on Content-Encoding (configurable)
• Redirects are no longer followed by default. Use .option(HttpOptions.followRedirects(true)) to change.

libraryDependencies +=  "org.scalaj" %% "scalaj-http" % "2.4.2"

<dependency>
  <groupId>org.scalaj</groupId>
  <artifactId>scalaj-http_${scala.version}</artifactId>
  <version>2.4.2</version>
</dependency>

If you're including this in some other public library. Do your users a favor and change the fully qualified name so they don't have version conflicts if they're using a different version of this library. The easiest way to do that is just to copy the source into your project :)

import scalaj.http._

val response: HttpResponse[String] = Http("http://foo.com/search").param("q","monkeys").asString
response.body
response.code
response.headers
response.cookies

Http(url) is just shorthand for a Http.apply which returns an immutable instance of HttpRequest. You can create a HttpRequest and reuse it:

val request: HttpRequest = Http("http://date.jsontest.com/")

val responseOne = request.asString
val responseTwo = request.asString

All the "modification" methods of a HttpRequest are actually returning a new instance. The param(s), option(s), header(s) methods always add to their respective sets. So calling .headers(newHeaders) will return a HttpRequest instance that has newHeaders appended to the previous req.headers

Http("http://foo.com/add").postForm(Seq("name" -> "jon", "age" -> "29")).asString

Note: the .oauth(...) call must be the last method called in the request construction

import scalaj.http.{Http, Token}

val consumer = Token("key", "secret")
val response = Http("https://api.twitter.com/oauth/request_token").postForm(Seq("oauth_callback" -> "oob"))
  .oauth(consumer).asToken

println("Go to https://api.twitter.com/oauth/authorize?oauth_token=" + response.body.key)

val verifier = Console.readLine("Enter verifier: ").trim

val accessToken = Http("https://api.twitter.com/oauth/access_token").postForm.
  .oauth(consumer, response.body, verifier).asToken

println(Http("https://api.twitter.com/1.1/account/settings.json").oauth(consumer, accessToken.body).asString)

Http("http://foo.com").{asString, asBytes, asParams}

Those methods will return an HttpResponse[String | Array[Byte] | Seq[(String, String)]] respectively

val response: HttpResponse[Map[String,String]] = Http("http://foo.com").execute(parser = {inputStream =>
  Json.parse[Map[String,String]](inputStream)
})

Http(url).postData(data).header("content-type", "application/json").asString.code

Http(url).postMulti(MultiPart("photo", "headshot.png", "image/png", fileBytes)).asString

You can also stream uploads and get a callback on progress:

Http(url).postMulti(MultiPart("photo", "headshot.png", "image/png", inputStream, bytesInStream,
  lenWritten => {
    println(s"Wrote $lenWritten bytes out of $bytesInStream total for headshot.png")
  })).asString

Http("http://httpbin.org/stream/20").execute(is => {
  scala.io.Source.fromInputStream(is).getLines().foreach(println)
})

note that you may have to wrap in a while loop and set a long readTimeout to stay connected

Http("https://localhost/").option(HttpOptions.allowUnsafeSSL).asString

Http(url).method("HEAD").asString

These are set to 1000 and 5000 milliseconds respectively by default

Http(url).timeout(connTimeoutMs = 1000, readTimeoutMs = 5000).asString

val response = Http(url).proxy(proxyHost, proxyPort).asString

The .option() method takes a function of type HttpURLConnection => Unit so you can manipulate the connection in whatever way you want before the request executes.

By default, the charset for all param encoding and string response parsing is UTF-8. You can override with charset of your choice:

Http(url).charset("ISO-8859-1").asString

You don't have to use the default Http singleton. Create your own:

object MyHttp extends BaseHttp (
  proxyConfig = None,
  options = HttpConstants.defaultOptions,
  charset = HttpConstants.utf8,
  sendBufferSize = 4096,
  userAgent = "scalaj-http/1.0",
  compress = true
)

scaladocs here

Some of the headers are locked by the java library for "security" reasons and the behavior is that the library will just silently fail to set them. You can workaround by doing one of the following:

• Start your JVM with this command line parameter: -Dsun.net.http.allowRestrictedHeaders=true
• or, do this first thing at runtime: System.setProperty("sun.net.http.allowRestrictedHeaders", "true")