iPhone base64 在发布到 php 脚本时损坏

Question

在我的应用程序中，用户裁剪那里的图片我将其编码为 base64 字符串并将其发送到我的 php 脚本。我正在使用 NSData+base64 类但是，当应用程序再次检索字符串以转换回图片我收到此错误：

Jan  8 14:21:33 Vessel.local Topic[11039] <Error>: ImageIO: JPEG Corrupt JPEG data:214        extraneous bytes before marker 0x68  Jan  8 14:21:33 Vessel.local Topic[11039] <Error>: ImageIO: JPEG Unsupported marker type 0x68

这是我发送数据的代码：

 NSString *urlString = [NSString stringWithFormat:@"http://myurl.php"];
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url                cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];
[request setHTTPMethod:@"POST"];
NSString *param = [NSString stringWithFormat:@"username=%@&password=%@&email=%@&quote=%@&pic=%@",user,password,email,quote,pic];
[request setHTTPBody:[param dataUsingEncoding:NSUTF8StringEncoding]];
NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request  delegate:self startImmediately:YES];

这是我在另一个视图控制器中取回它并尝试将其转回图像的时候

 -(void)connectionDidFinishLoading:(NSURLConnection *)connection{

homeData = [NSJSONSerialization JSONObjectWithData:responseData options:nil error:nil];

NSString *decodeString = [[homeData objectAtIndex:0]objectForKey:@"profile_pic" ];
decodeString = [decodeString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
int returnNUM = [decodeString length];
NSLog(@"RETURN STRING=%d",returnNUM);
NSData *data = [[NSData alloc] initWithData:[NSData dataFromBase64String:decodeString]];

profilepic = [[UIImageView alloc]initWithFrame:CGRectMake(5, 4, 120, 120)];
profilepic.image = [UIImage imageWithData:data];
UIGraphicsBeginImageContextWithOptions(profilepic.bounds.size, NO, 1.0);
[[UIBezierPath bezierPathWithRoundedRect:profilepic.bounds cornerRadius:80.0] addClip];
[pic drawInRect:profilepic.bounds];
profilepic.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self.view addSubview:profilepic];
 }

一旦我发布它，我如何防止图像被损坏..或者一旦我把它拿回来，我该如何清理它或防止发生损坏！这让我发疯了。非常感谢您提供一些代码的明确答案。谢谢

这是我在发送之前将图像转换为 base64 的代码。

    NSData *imageData = UIImageJPEGRepresentation(crop, 1.0);
    NSString *baseString = [imageData base64EncodedString];
    int original =[baseString length];
    NSLog(@"orignal String=%d",original);
    [self register:username.text withPass:password.text withEmail:email.text withQuote:quote.text withPic:baseString];

Answer 1

为什么要调用“stringByTrimmingCharactersInSet”？在我看来，这似乎是为了删除编码图像可能需要的字符......

编辑以包含我正在使用的一些代码中的示例，该代码将几个图像正确嵌入到要提交到 php 页面的 http 表单中。

我在 NSMutableData 上使用以下类别...

NSMutableData+HTTP.h里面有以下内容

@interface NSMutableData (HTTP)

-(void)appendFileAtPath:(NSString*)fullFilePath withFormKey:(NSString*)formKey withSuggestedFileName:(NSString*)suggestedFileName boundary:(NSData*)boundary;
-(void)appendKey:(NSString*)key value:(NSString*)value boundary:(NSData*)boundary;

@end

NSMutableData+HTTP.m里面有以下内容

#import "NSMutableData+HTTP.h"

@implementation NSMutableData (HTTP)

//use for attaching a file to the http data to be posted
-(void)appendFileAtPath:(NSString*)fullFilePath withFormKey:(NSString*)formKey withSuggestedFileName:(NSString*)suggestedFileName boundary:(NSData*)boundary{

    [self appendData:boundary]; 

    [self appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"%@\"\r\n", formKey, suggestedFileName] dataUsingEncoding:NSUTF8StringEncoding]];

    [self appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

    [self appendData:[NSData dataWithContentsOfFile:fullFilePath]];

    [self appendData:[@"Content-Encoding: gzip\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

    [self appendData:boundary]; 
}

//use for attaching a key value pair to the http data to be posted
-(void)appendKey:(NSString*)key value:(NSString*)value boundary:(NSData*)boundary{    
    [self appendData:boundary]; 
    [self appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", key] dataUsingEncoding:NSUTF8StringEncoding]];
    [self appendData:[value dataUsingEncoding:NSUTF8StringEncoding]];
    [self appendData:boundary]; 
}

@end

然后在创建 http 表单提交的代码中，我执行以下操作以将一对图像和键值对（通过上面的类别方法）附加到表单...（注意：我没有包含 NSURLConnectionDelegate 方法如果您想跟踪表单提交的进度，则需要实施。）

NSString *boundaryString = @"0xKhTmLbOuNdArY";
NSData *boundaryData = [[NSString stringWithFormat:@"\r\n--%@\r\n", boundaryString] dataUsingEncoding:NSUTF8StringEncoding];
NSString *phpReceiverURL = @"http://www.someurl.com/somephppage.php";

NSMutableURLRequest *theRequest = [[NSMutableURLRequest alloc] init];
[theRequest setTimeoutInterval:30];
[theRequest setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[theRequest setHTTPShouldHandleCookies:NO];
[theRequest setURL:[NSURL URLWithString:phpReceiverURL]];
[theRequest setHTTPMethod:@"POST"]; 

[theRequest addValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundaryString] forHTTPHeaderField: @"Content-Type"];
NSMutableData *body = [NSMutableData data];

//add some image files to the form
[body appendFileAtPath:[imagePath stringByAppendingPathComponent:@"cat.jpg"] 
    withFormKey:@"cat"  
    withSuggestedFileName:@"received-cat.jpg"
    boundary:boundaryData
];

[body appendFileAtPath:[imagePath stringByAppendingPathComponent:@"dog.jpg"] 
    withFormKey:@"dog"  
    withSuggestedFileName:@"received-dog.jpg"
    boundary:boundaryData
];

//add some key value pairs to the form
[body appendKey:@"testkeyone" value:@"testvalueone" boundary:boundaryData]; 
[body appendKey:@"testkeytwo" value:@"testvaluetwo" boundary:boundaryData]; 

// setting the body of the post to the reqeust
[theRequest setHTTPBody:body];

//create the connection
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];

另外请注意，我没有在我的应用程序之外测试过这个，所以我可能忘记了一些东西（例如我在上面的示例中没有定义的“imagePath” - 你必须为你的图像指定一个路径） ，但它应该让您很好地了解如何将一些图像附加到要提交到 php 页面的表单上。

希望这会有所帮助！