I have a request that works with curl at the command line: ```curl -A "ellens-user-agent" -X POST -d...

# http4k

[Ellen Spertus]

I have a request that works with curl at the command line:

curl -A "ellens-user-agent" -X POST -d 'grant_type=password&username=USER&password=PASSWORD' --user 'SCRIPTID:SECRET' <https://www.reddit.com/api/v1/access_token>

How do I convert that into an http4k request?

[Andrew O'Hara]

val request = Request(<http://Method.POST|Method.POST>, "<https://www.reddit.com/api/v1/access_token>")
    .withBasicAuth(Credentials("SCRIPTID", "SECRET"))
    .header("User-Agent", "ellens-user-agent")
    .body("grant_type=password&username=USER&password=PASSWORD")

-A is just a shortcut to set the User-Agent header
--user is just a shortcut to provide credentials for the authentication challenge; in this case, we just want basic
-d just sets the HTTP body. In this case, I'm sending it as a string, but http4k has controls for typesafe form bodies: https://www.http4k.org/guide/howto/use_html_forms/

[Ellen Spertus]

Thanks! I should have mentioned it was the --user field that I didn't know how to convert.

[Ellen Spertus]

I haven't been able to find nontrivial examples of using http4k as a client of an existing API.

[Andrew O'Hara]

Once you start getting the hang of authorizing and sending requests, you might want to swap this request out for the built-in oauth security filters.

https://www.http4k.org/guide/reference/oauth/

[Andrew O'Hara]

Because all that request is doing is performing the OAuth 2.0 Resource-Owner Password grant

[Ellen Spertus]

Thanks for the advice. I want to interface with the Reddit API, which may be a mistake because they don't have an OpenAPI spec, just the one shown. https://www.reddit.com/dev/api

[Andrew O'Hara]

OpenAPI specs are nice, but I'm sure you can build a custom client.

[Ellen Spertus]

I'm thinking I'll switch to a different API since I'm teaching a class and am creating an assignment for students. I think it would be more useful to show them how to integrate with a compliant API than implement a special case (which I'd have to do).

[Andrew O'Hara]

httpbin has a spec. Very useful playground for testing requests.

https://httpbin.org/#/

[s4nchez]

A couple of minor additions to @Andrew O'Hara’s answer:

val request = Request(<http://Method.POST|Method.POST>, "<https://www.reddit.com/api/v1/access_token>")
    .withBasicAuth(Credentials("SCRIPTID", "SECRET"), "Authorization")
    .header("User-Agent", "ellens-user-agent")
    .form("grant_type", "password")
    .form("username", "USER")
    .form("password", "PASSWORD")

One can use .form to define each data key pair individually.

Also, you can use request.toCurl() to see the curl version of that request and check/run the request in the command line. For the example above it generates:

curl -X POST -H "Authorization:Basic U0NSSVBUSUQ6U0VDUkVU" -H "User-Agent:ellens-user-agent" --data "grant_type=password&username=USER&password=PASSWORD" "<https://www.reddit.com/api/v1/access_token>"

[James Richardson]

Hey Ellen. It is very interesting you are using http4k in a class... are you able to share a bit on what sort of class it is? Maybe there are already some materials that could help.. or maybe we could collate some?

[Andrew O'Hara]

@s4nchez I had no idea there were form shortcuts like that. Good to know!

[Ellen Spertus]

I ended up using someone else's Java wrapper for Reddit rather than making my own, but thanks for the help.