Base64 Over HTTP POST丢失数据(Objective-C)

Question

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.

我将Base64输出到XCodes控制台,复制并粘贴它,它完美地工作.虽然我在数据库(MongoDB,纯文本文件等)中存储的Base64总是在另一端出现损坏.

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):http://dontpanicrabbit.com/api/grabimage.php

如果你查看源代码,你会发现它们是相同的,但是在破碎版本中添加了空格.

我使用的Objective-C代码是:

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
    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？

Answer 1

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,接收者知道'+'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.

初始数据中的"+"字符在接收和存储时变为"'.然后,当您输出该值时,它是无效的base64编码数据.

如果您检查工作与非工作示例的来源,您将看到原始Base64编码值中存在"+"的情况下,空格确实存在.你看到的任何换行都是因为你正在查看的来源是在''字符包裹行.

在您的iOS代码中,您需要正确编码base64编码的值,在您的情况下,您真正​​需要做的是对"+"字符进行百分比编码.

编辑添加,以回应评论:

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