Getting NSXMLParserErrorDomain error 4 while uploading uiimage to server through webservice

Question

I'm trying to post an image to a web service from the iPhone. I'll post the code first then explain everything I've tried:

NSData *Imagedata;
Imagedata = UIImagePNGRepresentation(imagee);
strSoapMsg = [[NSString alloc] initWithFormat:
                  @"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
                  "<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap12=\"http://www.w3.org/2003/05/soap-envelope\">"
                  "<soap12:Body>"
                  "<SaveMerchantImageFromIPhone xmlns=\"http://tempuri.org/\">"
                  "<byteArrayImage>%@</byteArrayImage>"
                  "<ProfileID>%d</ProfileID>"
                  "</SaveMerchantImageFromIPhone>"
                  "</soap12:Body>"
                  "</soap12:Envelope>", [NSData dataWithData:Imagedata],merchantProfileID];
// strSoapMsg = [[NSString alloc] initWithFormat:@"%@,%d",Imagedata,merchantProfileID];
//---print it to the Debugger Console for verification---
NSLog(@"soapMsg..........%@",strSoapMsg);

NSString *str_url = [ NSString stringWithFormat:@"%@user.asmx",xmlWebservicesUrl];
NSURL *url = [NSURL URLWithString:str_url];
req = [NSMutableURLRequest requestWithURL:url];

//---set the headers---

NSString *msgLength = [NSString stringWithFormat:@"%d",[strSoapMsg length]];
[req addValue:@"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
[req addValue:@"http://tempuri.org/SaveMerchantImageFromIPhone"  forHTTPHeaderField:@"SOAPAction"];
[req addValue:msgLength forHTTPHeaderField:@"Content-Length"];

//---set the HTTP method and body---

[req setHTTPMethod:@"POST"];
[req setHTTPBody: [strSoapMsg dataUsingEncoding:NSUTF8StringEncoding]];


conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
if (conn)
{
    webSaveMerchantImageFromIphone = [[NSMutableData data] retain];
}

I think it fails because the %@ format specifier takes an object. But I am not sure.

Answer 1

You are probably parsing an empty xml as your request is sent asynchronously and you don't wait for the response.
You should use the delegate methods
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data to concatenate the data you receive and
-(void)connectionDidFinishLoading:(NSURLConnection *)connection to start the parser.
Have a look at the NSURLConnectionDelegate protocol: https://developer.apple.com/library/mac/#documentation/Foundation/Reference/NSURLConnectionDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intf/NSURLConnectionDelegate

Answer 2

Here is how I interface with web-services. Definitely not the only way to do things and probably not the most popular, but highly secure and very fast. First off, my web-services are POST based. All the parameters are POSTed to the web-service which gives me cross platform independence (I use both PHP and .NET based web-services). I include an APIKey with all the web-service calls which maintains security in that ONLY the iOS app can communicate with the web-service. It also gives me the ability to change that APIKey and force users to update to newer versions of the application if needed (not something I have done yet, but it's there if I need to use it. This class depends on and uses AFNetworking. I have used several different libraries for network communication (including the iOS included frameworks), and have found AFNetworking to be very useful and efficient for what I am doing.

Here is the interface file for my class:

/*
 NetworkClient.h

 Created by LJ Wilson on 2/3/12.
 Copyright (c) 2012 LJ Wilson. All rights reserved.
 License:

 Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
 and associated documentation files (the "Software"), to deal in the Software without restriction, 
 including without limitation the rights to use, copy, modify, merge, publish, distribute, 
 sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all copies or 
 substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT 
 NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT 
 OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#import <Foundation/Foundation.h>

extern NSString * const APIKey;

@interface NetworkClient : NSObject

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                          block:(void (^)(id obj))block;

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
                          block:(void (^)(id obj))block;

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
             alertUserOnFailure:(BOOL)alertUserOnFailure
                          block:(void (^)(id obj))block;

+(void)processFileUploadRequestWithURL:(NSString *)url 
                             andParams:(NSDictionary *)params 
                              fileData:(NSData *)fileData 
                              fileName:(NSString *)fileName
                              mimeType:(NSString *)mimeType 
                                 block:(void (^)(id obj))block;

+(void)handleNetworkErrorWithError:(NSError *)error;

+(void)handleNoAccessWithReason:(NSString *)reason;

@end

And the Implementation file:

/*
 NetworkClient.m

 Created by LJ Wilson on 2/3/12.
 Copyright (c) 2012 LJ Wilson. All rights reserved.
 License:

 Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
 and associated documentation files (the "Software"), to deal in the Software without restriction, 
 including without limitation the rights to use, copy, modify, merge, publish, distribute, 
 sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all copies or 
 substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT 
 NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT 
 OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#import "NetworkClient.h"
#import "AFHTTPClient.h"
#import "AFHTTPRequestOperation.h"
#import "SBJson.h"

NSString * const APIKey = @"YourAPIKeyGoesHereIfYouChooseToUseIt";

@implementation NetworkClient

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                          block:(void (^)(id obj))block {

    [self processURLRequestWithURL:url andParams:params syncRequest:NO alertUserOnFailure:NO block:^(id obj) {
        block(obj);
    }];
}

+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
                          block:(void (^)(id obj))block {
    [self processURLRequestWithURL:url andParams:params syncRequest:syncRequest alertUserOnFailure:NO block:^(id obj) {
        block(obj);
    }];
}


+(void)processURLRequestWithURL:(NSString *)url 
                      andParams:(NSDictionary *)params 
                    syncRequest:(BOOL)syncRequest
             alertUserOnFailure:(BOOL)alertUserOnFailure
                          block:(void (^)(id obj))block {

    // Default url goes here, pass in a nil to use it
    if (url == nil) {
        url = @"DefaultURLGoesHere";
    }

    NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithDictionary:params];
    [dict setValue:APIKey forKey:@"APIKey"];

    NSDictionary *newParams = [[NSDictionary alloc] initWithDictionary:dict];

    NSURL *requestURL;
    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:requestURL];

    NSMutableURLRequest *theRequest = [httpClient requestWithMethod:@"POST" path:url parameters:newParams];

    __block NSString *responseString = @"";

    AFHTTPRequestOperation *_operation = [[AFHTTPRequestOperation alloc] initWithRequest:theRequest];
    __weak AFHTTPRequestOperation *operation = _operation;

    [operation  setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        responseString = [operation responseString];

        id retObj = [responseString JSONValue];

        // Check for invalid response (No Access)
        if ([retObj isKindOfClass:[NSDictionary class]]) {
            if ([[(NSDictionary *)retObj valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                block(nil);
                [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
            }
        } else if ([retObj isKindOfClass:[NSArray class]]) {
            if ([(NSArray *)retObj count] > 0) {
                NSDictionary *dict = [(NSArray *)retObj objectAtIndex:0];
                if ([[dict valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                    block(nil);
                    [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
                }
            }
        }
        block(retObj);
    } 
                                      failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                                          NSLog(@"Failed with error = %@", [NSString stringWithFormat:@"[Error]:%@",error]);
                                          block(nil);
                                          if (alertUserOnFailure) {
                                              // Let the user know something went wrong
                                              [self handleNetworkErrorWithError:operation.error];
                                          }

                                      }];

    [operation start];

    if (syncRequest) {
        // Process the request syncronously
        [operation waitUntilFinished];
    } 


}


#pragma mark - processFileUpload
+(void)processFileUploadRequestWithURL:(NSString *)url 
                             andParams:(NSDictionary *)params 
                              fileData:(NSData *)fileData 
                              fileName:(NSString *)fileName
                              mimeType:(NSString *)mimeType 
                                 block:(void (^)(id obj))block {

    // Default url goes here, pass in a nil to use it
    if (url == nil) {
        url = @"DefaultURLGoesHere";
    }

    NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithDictionary:params];
    [dict setValue:APIKey forKey:@"APIKey"];

    NSDictionary *newParams = [[NSDictionary alloc] initWithDictionary:dict];
    AFHTTPClient *client= [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:url]];  

    NSMutableURLRequest *myRequest = [client multipartFormRequestWithMethod:@"POST" 
                                                                       path:@"" 
                                                                 parameters:newParams 
                                                  constructingBodyWithBlock: ^(id <AFMultipartFormData>formData) {
        [formData appendPartWithFileData:fileData name:fileName fileName:fileName mimeType:mimeType];
    }];


    AFHTTPRequestOperation *_operation = [[AFHTTPRequestOperation alloc] initWithRequest:myRequest];
    __weak AFHTTPRequestOperation *operation = _operation;
    __block NSString *responseString = @"";

    [operation  setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        responseString = [operation responseString];

        id retObj = [responseString JSONValue];

        // Check for invalid response (No Access)
        if ([retObj isKindOfClass:[NSDictionary class]]) {
            if ([[(NSDictionary *)retObj valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                block(nil);
                [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
            }
        } else if ([retObj isKindOfClass:[NSArray class]]) {
            if ([(NSArray *)retObj count] > 0) {
                NSDictionary *dict = [(NSArray *)retObj objectAtIndex:0];
                if ([[dict valueForKey:@"Message"] isEqualToString:@"No Access"]) {
                    block(nil);
                    [self handleNoAccessWithReason:[(NSDictionary *)retObj valueForKey:@"Reason"]];
                }
            }
        }
        block(retObj);


    } 
                                      failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                                          NSLog(@"Failed with error = %@", [NSString stringWithFormat:@"[Error]:%@",error]);
                                          block(nil);
                                      }];

    [operation start];


}


#pragma mark - Error and Access Handling
+(void)handleNetworkErrorWithError:(NSError *)error {
    NSString *errorString = [NSString stringWithFormat:@"[Error]:%@",error];

    // Standard UIAlert Syntax
    UIAlertView *myAlert = [[UIAlertView alloc] 
                            initWithTitle:@"Connection Error" 
                            message:errorString 
                            delegate:nil 
                            cancelButtonTitle:@"OK" 
                            otherButtonTitles:nil, nil];

    [myAlert show];

}

+(void)handleNoAccessWithReason:(NSString *)reason {
    // Standard UIAlert Syntax
    UIAlertView *myAlert = [[UIAlertView alloc] 
                            initWithTitle:@"No Access" 
                            message:reason 
                            delegate:nil 
                            cancelButtonTitle:@"OK" 
                            otherButtonTitles:nil, nil];

    [myAlert show];

}


@end

And a sample call:

UIImage *image = [UIImage imagedNamed@"MyImage.png"]; 
NSData *imageData = UIImagePNGRepresentation(image);
NSString *filename = @"MyImage.png";

params = [NSDictionary dictionaryWithObjectsAndKeys:
                                @"Param1Value", @"Param1Name",
                                fileName, @"Filename",
                                nil];

[NetworkClient processFileUploadRequestWithURL:nil
                                     andParams:params 
                                      fileData:imageData 
                                      fileName:fileName
                                      mimeType:@"image/png" 
                                             block:^(id obj) {
    // Do something   
}];

If you have any questions, let me know.