Base64 Over HTTP POST丢失数据（Objective-C） [英] Base64 Over HTTP POST losing data (Objective-C)

问题描述

我目前有一个HTTP POST请求和一个Base64编码库，我将我的图像编码为B64，然后通过POST方法通过HTTP发送它。

I currently have a HTTP POST Request and a Base64 Encoding Library, I encode my image to B64 then send it over HTTP via the POST method.

我输出了Base64到XCodes控制台，复制并粘贴它，它完美地工作。虽然数据库中存储的Base64 I（MongoDB，纯文本文件等）总是在另一端损坏。

I output the Base64 to XCodes console, copy and paste it and it works perfectly. Although the Base64 I store within the Database (MongoDB, Plain Text File etc) always comes out corrupt on the other end.

工作版本（从XCode复制并粘贴）： http://dontpanicrabbit.com/api/working.php
破碎版（来自MongoDB数据库）：< a href =http://dontpanicrabbit.com/api/grabimage.php> http://dontpanicrabbit.com/api/grabimage.php

Working Version (Copied and Pasted from XCode): http://dontpanicrabbit.com/api/working.php Broken Version (From MongoDB Database): http://dontpanicrabbit.com/api/grabimage.php

如果您查看源代码，您会发现它们是相同的，但是在破碎的版本中添加了空格。

If you view the source you'll notice they are the same but there is added whitespace into the broken version.

我使用的Objective-C代码是：

The Objective-C code I am using is:

MyImage.image = [info objectForKey:UIImagePickerControllerOriginalImage];

    NSData *imageData = UIImageJPEGRepresentation(MyImage.image, 0);

    [Base64 initialize];
    NSString *encoded = [Base64 encode:imageData];

    NSString *urlPOST = encoded;
    //NSLog(@"%@",encoded);

    NSString *varyingString1 = @"picture=";
    NSString *varyingString2 = urlPOST;
    NSString *post = [NSString stringWithFormat: @"%@%@", varyingString1, varyingString2];
    NSLog(@"%@", post);
    //NSString *post = @"image=%@",urlPOST;
    NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

    NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];

    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString:@"url/api/insertimage.php"]];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:postData];
    NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: nil error: nil];
    NSString *strResult = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

PHP - > MongoDB存储

PHP -> MongoDB Storage

<?php
    try {
      // open connection to MongoDB server
      $conn = new Mongo('localhost');

      // access database
      $db = $conn->dablia;

      // access collection
      $collection = $db->images;

      // insert a new document
      $item = array(
        'picture' => $_POST['picture']
      );
      $collection->insert($item);
      echo 'Inserted document with ID: ' . $item['_id'];

      // disconnect from server
      $conn->close();
    } catch (MongoConnectionException $e) {
      die('Error connecting to MongoDB server');
    } catch (MongoException $e) {
      die('Error: ' . $e->getMessage());
    }
?>

输出代码：

<?php
try {
  // open connection to MongoDB server
  $conn = new Mongo('localhost');

  // access database
  $db = $conn->dablia;

  // access collection
  $collection = $db->images;

  // execute query
  // retrieve all documents
  $cursor = $collection->find();

  // iterate through the result set
  // print each document
  foreach ($cursor as $obj) {
    echo '<img src="data:image/jpeg;base64,'.trim($obj['picture']).'">';
  }

  // disconnect from server
  $conn->close();
} catch (MongoConnectionException $e) {
  die('Error connecting to MongoDB server');
} catch (MongoException $e) {
  die('Error: ' . $e->getMessage());
}
?>

我不知道为什么我似乎在破坏POST？

I have no idea why I seem to be corrupting over POST?

推荐答案

问题正是我在第一次评论中提出的问题。也就是说，base64编码数据可以包含+字符。在x-www-form-urlencoded数据中，接收器知道'+'是空格字符的编码。因此，由于您不是对base64值进行URL编码，因此任何+实例都会导致数据在收到时被破坏。

The problem is exactly what I suggested in my first comment. That is, base64 encoded data can contain '+' characters. In x-www-form-urlencoded data the receiver knows that '+' is an encoding of a space character. Thus since you aren't URL encoding your base64 value, any instances of '+' will cause the data to be corrupted when received.

您的'+'字符初始数据在接收和存储时变为''。当您输出该值时，它是无效的base64编码数据。

The '+' characters in your initial data are turning into ' ' when received and stored. When you then output that value, it is invalid base64 encoded data.

如果您检查工作与非工作示例的来源，您将看到空白存在于原始Base64编码值中存在+的位置。您看到的任何换行都是因为您查看源代码的是将字符包裹在''字符处。

If you examine the source of your working vs. non-working examples you'll see that the whitespace exists EXACTLY where there is a '+' in the original Base64 encoded value. Any newlines you're seeing are because whatever you're viewing the source in is wrapping lines at a ' ' character.

在您的iOS代码中，您需要正确编码base64编码值，在你的情况下，你真正需要做的就是对'+'字符进行百分比编码。

In your iOS code you need to properly encode the base64 encoded value, in your case all you really need to do is percent encode the '+' characters.

编辑添加，以回应评论：

EDIT to add, in response to comment:

post = [post stringByReplacingOccurrencesOfString:@"+" withString:@"%2B"];

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