如何使用Swift将图像从iOS上传到Ruby/Rails服务器

Question

我有一个ruby/rails应用程序，我希望在JSON请求有效内容中以Base64格式接受图像上传。基本的应用程序结构如下：

import UIKit 
import MapKit 

class NewCafeDetailsTableViewController: UITableViewController, NSURLConnectionDataDelegate { 

    @IBOutlet weak var submitButton: UIButton! 
    @IBOutlet weak var mainImageCell: AddImageCell! 
    var submitData: Dictionary<String, AnyObject>! 

    override func viewDidLoad() { 
     submitData = ["name": "Brian"] 
     submitButton.addTarget(self, action: Selector("submit"), forControlEvents: UIControlEvents.TouchUpInside) 
    } 

    func submit() { 
     // I\'ve tried to submit a dynamic image, but I switched it to a 
     // hard-coded 1x1 GIF just to get a grip on how to do this on 
     // the backend before attempting too much more 
     submitData["thumbnail_data"] = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" 
     var error: NSError? 

     var submitJSON: NSData! 
     submitJSON = NSJSONSerialization.dataWithJSONObject(submitData, options: NSJSONWritingOptions.PrettyPrinted, error: &error) 
     if (error == nil) { 
      let submitJSONString = NSString(data: cafeJSON, encoding: NSUTF8StringEncoding) 
      var url = NSURL(string: "http://localhost:3000/people.json") 
      var request = NSMutableURLRequest(URL: url!) 
      var requestData = submitJSONString?.dataUsingEncoding(NSUTF8StringEncoding) 
      request.HTTPBody = requestData 
      request.HTTPMethod = "POST" 
      request.setValue("application/json", forHTTPHeaderField: "Content-type") 
      request.setValue("application/json", forHTTPHeaderField: "Accept") 
      request.timeoutInterval = 10 

     } 
    } 

    func connection(connection: NSURLConnection, didReceiveResponse response: NSURLResponse) { 
     var response = response as NSHTTPURLResponse 

      if (response.statusCode >= 200 && response.statusCode <= 299) { 
       self.navigationController?.popViewControllerAnimated(true) 
       var alert = UIAlertView(title: "Success", message: "Cafe was successfully submitted. We'll review it in a few business days.", delegate: self, cancelButtonTitle: "Ok") 
       alert.show() 
      } else { 
       var alert = UIAlertView(title: "Oops..", message: "It seems there was some kind of server error, please try again later", delegate: self, cancelButtonTitle: "Ok") 
       alert.show() 
      } 


    } 

    func connection(connection: NSURLConnection, didFailWithError error: NSError) { 
     self.dismissViewControllerAnimated(true, completion: { 
      var alert = UIAlertView(title: "Oops..", message: "It seems there was some kind of server error, please try again later", delegate: self, cancelButtonTitle: "Ok") 
      alert.show() 

     }) 
    } 

} 

在我的Ruby代码我已经尝试了各种不同的回形针的选择，这似乎附近的残破。我也试着解码Base64，并自己保存，几乎没有成功。

一些我试过的东西：

data = Base64.decode64(params[:thumbnail_data]) 
File.open("test.jpg", "wb") do |f| f.write data end 

data = Base64.decode64(params[:thumbnail_data].split(",")[-1]) 
File.open("test.jpg", "wb") do |f| f.write data end 

好像不管我做什么，每当我试图打开上传的图片预览说，该文件已损坏。这个问题可能与NSData的排序有关吗？或者我没有正确格式化Base64？我尝试过使用各种宝石。

Answer 1

你可以设置你的thumbnail_data只是Base64的代码，如下图所示，改变请求的HTTP体：

var submitData: Dictionary<String, AnyObject>! 
submitData = ["name": "Brian"] 
submitData["thumbnail_data"] = "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" 

let session = NSURLSession.sharedSession() 
let request = NSMutableURLRequest(URL: NSURL(string: "http://localhost:3000/people")!) 
request.setValue("application/json", forHTTPHeaderField: "Content-Type") 
request.HTTPBody = try! NSJSONSerialization.dataWithJSONObject(submitData, options: []) 
request.HTTPMethod = "POST" 

let task = session.dataTaskWithRequest(request) { 
    (data: NSData?, response: NSURLResponse?, error: NSError?) in 
    //Handle server response 
} 
task.resume() 

特别是如果你想直接从设备上载的图像，在这种情况下，你应该先创建的表示，然后对其进行编码：

let jpegRep = UIImageJPEGRepresentation(image!, 0.75) 
let base64Image = jpegRep!.base64EncodedStringWithOptions([]) 

当图像是UIImage对象和0.75是图像质量

在服务器端，如果你使用回形针宝石，你应该有这样的事情：

image = StringIO.new(Base64.decode64(params[:thumbnail_data])) 
Something.create(:image => image) 

希望这有助于

Answer 2

我有一个类似的问题，后头痛几天来解：

只需更换self.capturePhotoView.image与图像

if let capturePhotoImage = self.capturePhotoView.image { 
    if let imageData = UIImagePNGRepresentation(capturePhotoImage) { 
     let encodedImageData = imageData.base64EncodedString(options: NSData.Base64EncodingOptions(rawValue: 0)) 
    } 
} 

，然后在你的服务器端假设Ÿ这样对其进行解码你在你的图像模型上有回形针。

image = StringIO.new(Base64.decode64(params[:image].tr(' ', '+'))) 
image.class.class_eval { attr_accessor :original_filename, :content_type } 
image.original_filename = SecureRandom.hex + '.png' 
image.content_type = 'image/png' 

create_image = Image.new(image: image) 
create_image.save! 

希望这有助于https://blog.kodius.io/2016/12/30/upload-image-from-swift-3-ios-app-to-rails-5-server/