How to write a POST request using Alamofire and swift 4 for the Clarifai API?

Question

I am relatively new to networking in Swift, and especially POST requests. I have read the documentation for the Clarifai API and for Alamofire, but haven't quite figured out how to write a working request using Alamofire. So far I have found the following piece of code which creates a structure that conforms to the API of Clarifai which wants the request to be structured like this:

curl -X POST \
  -H "Authorization: Key YOUR_API_KEY" \
 -H "Content-Type: application/json" \
-d @https://api.clarifai.com/v2/models/aaa03c23b3724a16a56b629203edc62c/outputs << FILEIN
 {
   "inputs": [
    {
    "data": {
      "image": {
        "base64": "$(base64 /home/user/image.png)"
      }
    }
  }
]
}
FILEIN

This is the swift code I found that achieves exactly that:

struct ImageObj: Codable { let base64: String }

    struct DataObj: Codable {
        let image: ImageObj
    }
    
    struct InputObj: Codable {
        let data: DataObj
    }
    
    struct InputsContainerObj: Codable {
        let inputs: [InputObj]
    }
    
    let imageObj = ImageObj(base64: "abc123")
    let dataObj = DataObj(image: imageObj)
    let inputObj = InputObj(data: dataObj)
    let inputsContainerObj = InputsContainerObj(inputs: [inputObj])
    
    let encoder = JSONEncoder()
    do {
        let jsonData = try encoder.encode(inputsContainerObj)
        let jsonString = String(data: jsonData, encoding: .utf8)!
        
        print(jsonString) //{"inputs":[{"data":{"image":{"base64":"abc123"}}}]}
    } catch _ as NSError {
        
    }

Now I have no idea what I should do after this point. I tried writing an Alamofire request using POST, but got stuck on parameters? and encodables? For parameters I tried something like:

let parameters: Parameters = [
        "Authorization: Key":"xxxxxxxxxxxxxxxxxxxxxxxx",
    "Content-Type":"application/json"]

But I don't know if it is correct. If anyone could help me out here I would greatly appreciate it! Have a nice day everyone!

Hi! I'm trying to setup clarifai's REST API with Alamofire too but can't seem to get it right. Did you find the solution? Thanks! — Karthik Kannan, Jul 13 '18 at 16:34
Interesting. I'm getting a invalid or malformed request error when i try to run my code. — Karthik Kannan, Jul 13 '18 at 16:37
Are you able to provide the error you're seeing exactly? What does the alamofire request look like (code for that if possible). Hard to know what could be going wrong here. — syntheticgio, Nov 02 '20 at 05:28
@KarthikKannan I know this question is fairly old, but I think the answer I added might also be what you're running into. — syntheticgio, Nov 02 '20 at 05:41

score 1 · Answer 1 · answered Nov 02 '20 at 05:40

It looks like you've constructed the jsonString from the object and also the headers (you've called them 'parameters'). You should be able to send via the following:

let headers: [String: AnyObject] = [
    "Authorization: Key":"xxxxxxxxxxxxxxxxxxxxxxxx",
    "Content-Type":"application/json"
]

Alamofire.request(.POST, "https://api.clarifai.com/v2/inputs", parameters: jsonString, headers: headers, encoding: .JSON)
    .responseJSON { request, response, JSON, error in
        print(response)
        print(JSON)
        print(error)
    }

I've re-named them as headers to make it more clear above. Please note, I've masked out the Authorization Key (both in the answer and in the original question) - generally you wouldn't want to share this to the public.

How to write a POST request using Alamofire and swift 4 for the Clarifai API?

1 Answers1