Curl Transport

Curl Transport is an open source software that allows you to use Go's native http.Client backed with curl.

It's a drop in replacement for http.Client's default transport.

The interface remains the same but http.Client would use libcurl to make the call.

Getting Started

Prerequisites

• libcurl headers (version >=7.10.0)
  • Ubuntu: sudo apt-get install libcurl4-openssl-dev
  • OSX: brew install curl
• Go (version >=1.7) (1.6 could work, not tested)

Get the package

go get -u github.com/umurkontaci/go-curl-transport/transport

Try it out

package main

import (
  "net/http"
  "io/ioutil"
  "log"

  "github.com/umurkontaci/go-curl-transport/transport"
)

func main() {
    cli := http.Client{Transport: transport.New()}
    res, err := cli.Get("https://httpbin.org/uuid")
    if err != nil {
        panic(err)
    }

    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        panic(err)
    }

    log.Print(body)
}

Why?

curl is an extremely mature piece of software that's well integrated with different systems. Most problems you can encounter with http clients are already solved problems in curl.

Putting this behind http.Client's transport allows you to keep the same, well-defined idiomatic go interface, but have all the power of curl.

For example, curl in OSX integrates with OSX's Keychain so any certificate that's trusted at the OS level will be trusted. No more concatanating certificates to a file.

Or if you are working with Kerberos or GSS, since curl integrates with Kerberos and GSS libraries really well, all you have to do is to set the flag and you have a GSSNEGOTIATE capable http Client.

import (
    "net/http"
    "github.com/umurkontaci/go-curl-transport/transport"
    "github.com/umurkontaci/go-curl"
)

func GssClient() (*http.Client, error) {
    t := transport.New()
    t.PostConfigure = func(c *curl.CURL, r *http.Request) error {
        err := c.Setopt(curl.OPT_HTTPAUTH, curl.AUTH_GSSNEGOTIATE)
        if err != nil {
            return nil, err
            }
        err = c.Setopt(curl.OPT_USERPWD, ":")
        if err != nil {
            return nil, err
        }
    }
    return http.Client{Transport: t}, nil
}

Caveats

• HTTP/2 is not supported (yet)
• This library is very new, so don't use it in production.