我正在调用一种Web服务方法来上传图像以及其他帖子参数。 我将图像数据转换为base64字符串，如果是多个图像，我使用逗号分隔的base64字符串。有时其他帖子参数在服务器上无法到达，有时会到达。 如果我上传1或2个小图像，代码可以正常工作，但如果我选择4-5个图像，则相同的代码会失败。 post参数中的base64字符串长度是否有任何限制？什么是最好的解决方案？
转换为base64的代码
+ (NSString*) getCommaSeperatedBase64ForImages:(NSArray*)imagesArray {
NSMutableArray* final = [NSMutableArray arrayWithCapacity:0];
if(imagesArray){
for (unsigned int i = 0;i<[imagesArray count];i++ ){
UIImage *image = [imagesArray objectAtIndex:i];
NSString *base64ImageString = nil;
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
base64ImageString = [[self class] encodeToBase64String:image];
}else{
//iOS < 7.0
NSData *imageData = UIImagePNGRepresentation(image);
base64ImageString = [[NSString alloc] initWithData:imageData encoding:NSUTF8StringEncoding];
base64ImageString = [imageData base64EncodedString];
}
if (base64ImageString) {
NSLog(@"Base 64 Encoded String is %@",base64ImageString);
[final addObject:base64ImageString];
}
}
}
if (final && [final count] > 0) {
return [[self class] getCommaSeperatedString:final];
}
return nil;
}
+ (NSString *)encodeToBase64String:(UIImage *)image {
return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}
+ (NSString*)getCommaSeperatedString:(NSArray*)anArray {
NSString *groupString = @"";
NSInteger counter = [anArray count];
for(unsigned int i = 0 ; i < counter; i++) {
NSString *emailStr = [anArray objectAtIndex:i];
if(i != counter-1)
groupString = [groupString stringByAppendingString:[NSString stringWithFormat:@"%@,",emailStr]];
else {
groupString = [groupString stringByAppendingString:emailStr];
}
}
return groupString;
}
+ (NSString *)encodeToBase64String:(UIImage *)image {
return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}
+ (NSString*)getCommaSeperatedString:(NSArray*)anArray {
NSString *groupString = @"";
NSInteger counter = [anArray count];
for(unsigned int i = 0 ; i < counter; i++) {
NSString *emailStr = [anArray objectAtIndex:i];
if(i != counter-1)
groupString = [groupString stringByAppendingString:[NSString stringWithFormat:@"%@,",emailStr]];
else {
groupString = [groupString stringByAppendingString:emailStr];
}
}
return groupString;
}
修改更多代码 我为每个帖子参数
创建了一个带键值对的NSDictionary对象 - (void) addNewListing:(NSDictionary*)params withCompletionBlock:(LHWebServiceCompletionBlock)block {
@try {
if (params == nil || [params count] == 0) {
[self showErrorAlertWithTitle:kErrorAlertTitle andMessage:@"Failed to add listings"];
return;
}
self.currentSelector = @selector(addNewListing:withCompletionBlock:);
self.currentParams = params;
self.completionBlock = block;
NSString* userID = [params valueForKey:@"userID"];
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@%@%@/%@",LH_BASE_API_URL,kAddNewListing,userID,kAPP_Key]];
NSString *post = [NSString stringWithFormat:@"%@",[params serializeParams:[params objectForKey:@"PostParameters"]]];
[self performURLRequestWith:url andRequestType:@"POST" andPostParamas:post];
}
@catch (NSException *exception) {
NSLog(@"Exception occured in add new listing %@",[exception description]);
}
}
static NSString *toString(id object) {
return [NSString stringWithFormat: @"%@", object];
}
// helper function: get the url encoded string form of any object
static NSString *urlEncode(id object) {
NSString *string = toString(object);
NSString *s = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)string,
NULL,
(CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
kCFStringEncodingUTF8));
return s;
}
@implementation NSDictionary (UrlEncoding)
-(NSString *)serializeParams:(NSDictionary *)params {
/*
Convert an NSDictionary to a query string
*/
NSMutableArray* pairs = [NSMutableArray array];
for (NSString* key in [params keyEnumerator]) {
id value = [params objectForKey:key];
if ([value isKindOfClass:[NSDictionary class]]) {
for (NSString *subKey in value) {
NSString* escaped_value = [value objectForKey:subKey];
[pairs addObject:[NSString stringWithFormat:@"%@[%@]=%@", urlEncode(key), urlEncode(subKey), urlEncode(escaped_value)]];
}
} else if ([value isKindOfClass:[NSArray class]]) {
for (NSString *subValue in value) {
NSString* escaped_value = subValue;
[pairs addObject:[NSString stringWithFormat:@"%@[]=%@", urlEncode(key), urlEncode(escaped_value)]];
}
} else {
NSString* escaped_value = [params objectForKey:key];
[pairs addObject:[NSString stringWithFormat:@"%@=%@", urlEncode(key), urlEncode(escaped_value)]];
//[escaped_value release];
}
}
return [pairs componentsJoinedByString:@"&"];
}
@end
网络服务方法
- (void)performURLRequestWith:(NSURL*)requestURL andRequestType:(NSString*)type andPostParamas:(NSString*)postData {
@try {
if (requestURL == nil || type == nil) {
if (self.completionBlock) {
NSError* error = [self generateErroWithMessage:@"Invalid URL"];
self.completionBlock(error,nil);
}
return;
}
myURLRequest = [[NSMutableURLRequest alloc] initWithURL:requestURL];
[myURLRequest setHTTPMethod:type];
[myURLRequest setTimeoutInterval:kRequestTimeOut];
if ([type isEqualToString:@"POST"]) {
if (postData == nil) {
NSError* error = [self generateErroWithMessage:@"Web Service Error"];
self.completionBlock(error,nil);
}
// NSString* encodedPost = [[self class] urlEncoded:postData];
NSData *requestData = [postData dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSString* requestDataLengthString = [NSString stringWithFormat:@"%d",[requestData length]];
[myURLRequest setHTTPBody:requestData];
[myURLRequest setValue:requestDataLengthString forHTTPHeaderField:@"Content-Length"];
NSLog(@"Post Params %@",postData);
NSLog(@"Register URL %@",requestURL);
//[requestData release];
//[requestDataLengthString release];
//self.currentConnection = [NSURLConnection connectionWithRequest:myURLRequest delegate:self];
}
if (self.currentConnection != nil) {
self.currentConnection = nil;
}
if (async) {
[NSURLConnection sendAsynchronousRequest:myURLRequest
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *serverData, NSError *connectionError) {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if ([serverData length] >0 && connectionError == nil && [httpResponse statusCode] == 200)
{
if ([serverData length] > 0 && connectionError == nil){
[self connection:nil didReceiveData:serverData];
// DO YOUR WORK HERE
[self connectionDidFinishLoading:nil];
}
}
}];
async = NO;
}
else {
self.currentConnection = [NSURLConnection connectionWithRequest:myURLRequest delegate:self];
}
}
@catch (NSException *exception) {
NSLog(@"Exception occured %@",[exception description]);
}
}
如果我使用1或2张图片，则上述代码有效，但如果使用4-5图像服务器发送给我，则其他帖子参数的值为null。