How to debug a ZIO HTTP Request value (a debug function)

By Alvin Alexander. Last updated: November 11, 2024

As a brief note, if you need to debug a ZIO HTTP Request value, I just created this function to return its values as a String, and it appears to work properly:

// for debugging
def formatRequest(request: Request): String =
    s"""
       |Method:  ${request.method}
       |Path:    ${request.path}
       |Headers: ${request.headers.map(h => s"${h.headerName}: ${h.renderedValue}").mkString("\n  ")}
       |URL:     ${request.url}
       |Query Params:   ${
           val params: QueryParams = request.url.queryParams
           if (params.isEmpty) "none"
           else (for ((k, v) <- params.map) yield s"$k: $v").mkString(", ")
       }
       |Remote Address: ${request.remoteAddress.getOrElse("unknown")}
       |""".stripMargin

Here’s an example of how to call that Request-debugging code:

// use it
Method.GET / "hello" / string("name") -> handler { (name: String, request: Request) =>
    println(formatRequest(request))
    Response.json(Greeting(s"Hello, $name!").toJson)
}

And this is what some sample output looks like:

# sample call:  curl "http://localhost:8080/hello/fred?a=foo&b=bar"
# output:
Method:  GET
Path:    /hello/fred
Headers: Host: localhost:8080
  User-Agent: curl/8.4.0
  Accept: */*
  content-length: 0
URL:     /hello/fred?a=foo&b=bar
Query Params: a: Chunk(foo), b: Chunk(bar)
Remote Address: /0:0:0:0:0:0:0:1

scala

convert

function

handler

http

How to debug a ZIO HTTP Request value (a debug function)

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