Can a lens be used to convert from `String` to `T` I have th

Question

Can a lens be used to convert from `String` to `T` I have the following hardcoded bodyString which I get from making a request via okHttp3 to Github s user API To me it seems like I might have to use some http4k specific way of doing this The documentation isn t clear to me as to how I should proceed doesn t mean it s lacking just that I don t understand it ``` val bodyString = login arnabkd id 1014699 trimIndent val lens = Body auto lt GithubUser gt toLens How to convert into GithubUser ```

Arnab · Answer

For more context the function in its entirety ```fun contextFnGithub request Request Principal val user = request cookie GithubAccessToken value let accessTokenString gt val response = httpClient newCall OkHttpRequest Builder header Accept application vnd github+json header Authorization token $accessTokenString url <https api github com user> get build execute println response val bodyString = login arnabkd id 1014699 trimIndent val lens = Body auto lt GithubUser gt toLens How to convert into GithubUser null TODO AnonymousUser return user ```

dave · Answer

The body lens you have is designed to extract inject an object from an http4k message object it doesn t deal with strings Under the covers it is using the Jackson Moshi object from which you import the auto method to call Jackson asA You can do the same upside down face

dave · Answer

If you use the http4k OkHttp client module to make the request you can bypass what you re trying to do and use the lens

Arnab · Answer

```val httpClient = OkHttpClient ```

dave · Answer

The uniform server client interface provided by Server as a Function model is one of the most powerful aspects of http4k you should definitely use it

dave · Answer

No use `OkHttp `

Arnab · Answer

Ah thanks

dave · Answer

dave · Answer

Suggest that you check out some of the talks on http4k concepts to see all the things we can do with it upside down face

dave · Answer

Arnab · Answer

I did It s one of the things that inspired me to give http4k a try for a side project smile It s just very challenging to get my head around because I come from a world that is very very different xD

dave · Answer

No problem we know that it s very different but beware once you ve used it it s very hard to go back to the old world wink

dave · Answer

But we re always here to answer questions about all this stuff and help upside down face

Arnab · Answer

Thanks That first link helped a lot smile Ended up with a neat little function like so ```fun contextFnGithub request Request Principal val user = request cookie GithubAccessToken value let accessTokenString gt val response = httpClient Request Method GET <https api github com user> header Accept application vnd github+json header Authorization token $accessTokenString when response status Status OK gt lens response else gt null AnonymousUser return user ```

dave · Answer

You can also use a Cookie lens wink

dave · Answer

And you can use a filter to add the Bearer token `ClientFilters BearerAuth token token then http request `

dave · Answer

Once you start looking http4k is function composition all the way down wink

dave · Answer

And the Accept header isn t required for that GitHub call btw wink wink