Vapor 3 - send a HTTPRequest

Question

How do you send an API request in Vapor 3 with the HTTPRequest struct?

I tried variations of the following code..

var headers: HTTPHeaders = .init()
let body = HTTPBody(string: a)            
let httpReq = HTTPRequest(
    method: .POST,
    url: URL(string: "/post")!,
    headers: headers,
    body: body)

let httpRes: EventLoopFuture<HTTPResponse> = HTTPClient.connect(hostname: "httpbin.org", on: req).map(to: HTTPResponse.self) { client in
    return client.send(httpReq)
}

The compile error Cannot convert value of type '(HTTPClient) -> EventLoopFuture<HTTPResponse>' to expected argument type '(HTTPClient) -> _'

I have tried other variations of code that worked.

Vapor 3 Beta Example Endpoint Request

let client = try req.make(Client.self)

let response: Future<Response> = client.get("http://example.vapor.codes/json")

I read and re-read:

I have tried other variations of code that worked - so you got it working some way but want to use HTTPRequest instead? — LinusGeffarth
hey @LinusGeffarth. I found a simpler way by using the higher level wrapper named Client. I found the comments for this Protocol were inside the code file of Client.swift very helpful. — rustyMagnet
For my future self (and anyone else): you need to do req.client().post(....), see docs in Client.swift, like rustyMagnet described above. — LinusGeffarth

JoannisO JoannisO · Accepted Answer · 2019-03-19T16:45:46

Your problem is .map(to: HTTPResponse.self). Map needs to transform its result into a new result regularly, like you would map an array. However, the result of your map-closure returns an EventLoopFuture<HTTPResponse>. This results in your map function returning an EventLoopFuture<EventLoopFuture<HTTPResponse>>.

To avoid this complexity, use flatMap.

var headers: HTTPHeaders = .init()
let body = HTTPBody(string: a)            
let httpReq = HTTPRequest(
    method: .POST,
    url: URL(string: "/post")!,
    headers: headers,
    body: body)

let client = HTTPClient.connect(hostname: "httpbin.org", on: req)

let httpRes = client.flatMap(to: HTTPResponse.self) { client in
    return client.send(httpReq)
}

EDIT: If you want to use the Content APIs you can do so like this:

let data = httpRes.flatMap(to: ExampleData.self) { httpResponse in
    let response = Response(http: httpResponse, using: req)
    return try response.content.decode(ExampleData.self)
}

Vapor 3 - send a HTTPRequest

2 Answers