Pronoid Android

Yeah, I know I said I wouldn't be posting much, but I've cleaned up and updated my HttpHelper class for one of my paid projects so that it supports cookies, form/multipart file uploads, non-ASCII characters, etc., so I thought I'd release it into the wild for y'all.

Apache License 2.0, as before.

The interface should be pretty self-evident from the .h file:

//
//  HttpHelper.h
//
//  Created by Jon Evans on 04/09/09.
//  Copyright 2009 Jon Evans. Apache 2.0 license.
//

#import <Foundation/Foundation.h>

@interface HttpHelper : NSObject {
}

//Convenience methods
+(NSURLRequestCachePolicy)getCachePolicyFor:(NSString *)urlString;

//Cookie handling
+(void) useCookies:(BOOL)use;
+(NSArray*) latestCookies;
+(void) getCookiesFrom:(NSHTTPURLResponse*)response forURL:(NSURL*)url;

//HTTP Posts
+(NSURLRequest*) buildPostRequestForURL:(NSString *)urlString withData:(NSDictionary*) data;
+(NSURLRequest *) buildRequestWithPostKeys:(NSArray *) postKeys postValues:(NSArray *) postValues urlString:(NSString *)urlString;
+(BOOL) doPost:(NSURLRequest *)request forCaller:(id)caller onSuccess:(SEL)successSelector onFailure:(SEL)failSelector;

//HTTP Gets
+(NSURLRequest *)getURLRequestFor:(NSString *)urlString;
+(BOOL) doGet:(NSString *)urlString forCaller:(id)caller onSuccess:(SEL)successSelector onFailure:(SEL)failSelector;

//Synchronized accessors
+(NSString *) doSynchronizedGet:(NSString *)urlString;
+(NSData *) doSynchronizedDataGet:(NSString *)urlString;
+(NSString *) doSynchronizedPostTo:(NSString *)urlString withRequest:(NSURLRequest*)request;
+(NSString *) doSynchronizedPostTo:(NSString *)urlString withData:(NSDictionary*)data;
+(NSString *) doSynchronizedPostTo:(NSString *)urlString withKeys:(NSArray*)postKeys andValues:(NSArray*)postValues;

//Form/multipart (for file upload)
+(NSString *) doSynchronizedMultipartPostTo:(NSString*)urlString withData:(NSDictionary*)data fileKeys:(NSArray*)fileKeys;
+(NSString *) doSynchronizedMultipartPostTo:(NSString*)urlString withKeys:(NSArray*)keys andValues:(NSArray*)values fileKeys:(NSArray*)fileKeys;

@end

...and here's where the magic happens:

//
//  HttpHelper.m
//
//  Created by Jon Evans on 04/09/09.
//  Copyright 2009 Jon Evans. Apache 2.0 license.
//

#import "HttpHelper.h"


@implementation HttpHelper

static HttpHelper *singleton=nil;
static NSArray *latestCookies=nil;
static BOOL useCookies=NO;


#pragma mark -
#pragma mark Singleton methods

+(HttpHelper *) getInstance {
 if (singleton==nil)
  singleton = [[[HttpHelper alloc] init] autorelease];
 return singleton;
}

+(id)allocWithZone:(NSZone *)zone {
 if (singleton == nil) {
  singleton = [super allocWithZone:zone];
  return singleton;
 }
 return nil;
}

-(id)copyWithZone:(NSZone *)zone {
 return self;
}

-(id)retain {
 return self;
}

-(NSUInteger)retainCount {
 return UINT_MAX;
}

-(void)release {
 //pass
}

-(id)autorelease {
 return self;
}

- (void)dealloc {
    [super dealloc];
}


#pragma mark -
#pragma mark Convenience methods

+(NSURLRequestCachePolicy)getCachePolicyFor:(NSString *)urlString {
 //Hived out to a separate method because we might fine-tune this later.
 return NSURLRequestUseProtocolCachePolicy;
 // return NSURLRequestReloadIgnoringCacheData;
}


#pragma mark -
#pragma mark Cookie handling

+(void) useCookies:(BOOL)use
{
 useCookies=use;
}

+(void) getCookiesFrom:(NSHTTPURLResponse*)response forURL:(NSURL*)url {
 if ([response class]==[NSHTTPURLResponse class])
  latestCookies = [NSHTTPCookie cookiesWithResponseHeaderFields:[response allHeaderFields] forURL:url];
}

+(NSArray*) latestCookies {
 return latestCookies;
}



#pragma mark -
#pragma mark HTTP Posts

+(NSURLRequest*) buildPostRequestForURL:(NSString *)urlString withData:(NSDictionary*) data
{
 NSArray *keys = [data allKeys];
 NSMutableArray *values = [NSMutableArray arrayWithCapacity:[keys count]];
 for (NSString *key in keys) {
  NSString *value = [data objectForKey:key];
  [values addObject:(value ? [NSString stringWithFormat:@"%@",value] : @"")];
 }
 return [self buildRequestWithPostKeys:keys postValues:values urlString:urlString];
}

+(NSURLRequest*) buildRequestWithPostKeys:(NSArray *) postKeys postValues:(NSArray *) postValues urlString:(NSString *)urlString {
 NSURL * url = [NSURL URLWithString:urlString];
 NSURLRequestCachePolicy policy = NSURLRequestReloadIgnoringCacheData; // we never want a cache of a post response
 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:policy timeoutInterval:30.0];
 [request setHTTPMethod:@"POST"];
 
 if (useCookies && latestCookies!=nil && [latestCookies count]>0) {
  NSDictionary * headers = [NSHTTPCookie requestHeaderFieldsWithCookies:latestCookies];
  [request setAllHTTPHeaderFields:headers];
 }
 
 NSMutableData *paramData =  [NSMutableData dataWithCapacity:8192];
 
 NSMutableString *params=[[NSMutableString alloc] initWithCapacity:1024];
 for (int i=0; i<[postValues count]; i++) {
  NSString *param = i>0 ? @"&" : @"";
  param = [param stringByAppendingFormat:@"%@=",[postKeys objectAtIndex:i]];
  [paramData appendData:[param dataUsingEncoding:NSUTF8StringEncoding]];
  
  NSObject* valueToPost = [postValues objectAtIndex:i];
  NSString *stringToPost = [valueToPost class]==[NSString class] ? (NSString*)valueToPost : [NSString stringWithFormat:@"%@",valueToPost];
  stringToPost = [stringToPost stringByReplacingOccurrencesOfString:@"&" withString:@"%26"];
  [paramData appendData:[stringToPost dataUsingEncoding:NSUTF8StringEncoding]];
 }
 
 NSString *msgLength = [NSString stringWithFormat:@"%d", [paramData length]];
 [request addValue: msgLength forHTTPHeaderField:@"Content-Length"];
 [request setHTTPBody: paramData];
 [params release];
 
 return request;
}

+(BOOL) doPost:(NSURLRequest *)request forCaller:(id)caller onSuccess:(SEL)onSuccess onFailure:(SEL)onFailure {
 
 NSArray *keys = [NSArray arrayWithObjects:@"request", @"caller", @"onSuccess", @"onFailure", nil];
 NSArray *values = [NSArray arrayWithObjects:request, caller,
        [NSValue valueWithBytes:&onSuccess objCType:@encode(SEL)],
        [NSValue valueWithBytes:&onFailure objCType:@encode(SEL)],
        nil];
 NSDictionary *args = [NSDictionary dictionaryWithObjects:values forKeys: keys];
 [NSThread detachNewThreadSelector:@selector(doHttp:) toTarget:[self getInstance] withObject:args];
 return TRUE;
}


#pragma mark -
#pragma mark HTTP Gets

+(NSURLRequest *)getURLRequestFor:(NSString *)urlString {
 NSURL *url = [NSURL URLWithString:urlString];
 NSURLRequestCachePolicy policy = [self getCachePolicyFor:urlString];
 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:policy timeoutInterval:30.0];
 [request setHTTPMethod:@"GET"];

 if (useCookies && latestCookies!=nil && [latestCookies count]>0) {
  NSDictionary * headers = [NSHTTPCookie requestHeaderFieldsWithCookies:latestCookies];
  [request setAllHTTPHeaderFields:headers];
 }
 return request;
}

+(BOOL) doGet:(NSString *)urlString forCaller:(id)caller onSuccess:(SEL)onSuccess onFailure:(SEL)onFailure {
 NSURLRequest *request = [self getURLRequestFor:urlString];
 NSArray *keys = [NSArray arrayWithObjects:@"request", @"caller", @"onSuccess", @"onFailure", nil];
 NSArray *values = [NSArray arrayWithObjects:request, caller,
        [NSValue valueWithBytes:&onSuccess objCType:@encode(SEL)],
        [NSValue valueWithBytes:&onFailure objCType:@encode(SEL)],
        nil];
 NSDictionary *args = [NSDictionary dictionaryWithObjects:values forKeys: keys];
 NSThread* uploadThread = [[NSThread alloc] initWithTarget:[self getInstance] selector:@selector(doHttp:) object:args];
 [uploadThread start];
 [uploadThread release];
 return TRUE;
}


#pragma mark -
#pragma mark Internals

-(BOOL) doHttp:(NSDictionary *)args
{
 @synchronized (self) {
  //autorelease pool
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  
  NSURLRequest *request = [args objectForKey:@"request"];
  NSObject *caller = [args objectForKey:@"caller"];
  
  SEL onSuccess;
  [[args objectForKey:@"onSuccess"] getValue:&onSuccess];
  SEL onFailure;
  [[args objectForKey:@"onFailure"] getValue:&onFailure];
  
  NSError *error=nil;
  NSHTTPURLResponse *response=nil;
  NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: &response error: &error ];
  NSString * responseString = [[[NSString alloc] initWithData: returnData encoding: NSUTF8StringEncoding] autorelease];
  
  NSString *errorString=nil;
  
  if (error)
   errorString = [NSString stringWithFormat:@"Error %@ '%@': %@",NSLocalizedString(@"loading page",nil), [request URL], [error localizedDescription]]; 
  else if (response==nil || returnData==nil)
   errorString = [NSString stringWithFormat:@"Error - %@ %@",NSLocalizedString(@"No response from URL",nil), [request URL]];
  else if (response.statusCode!=200)
   errorString = [NSString stringWithFormat:@"Error - %@ %i %@ %@",NSLocalizedString(@"HTTP Error",nil), response.statusCode, NSLocalizedString(@"from URL",nil), [request URL]];
  
  if (errorString && [errorString length]>0) {
   NSLog(@"iTravel Error ",errorString);
   [caller performSelectorOnMainThread: onFailure withObject:errorString waitUntilDone:NO];
  }
  else {
   if (useCookies)
    [HttpHelper getCookiesFrom:response forURL:[request URL]];
   [caller performSelectorOnMainThread: onSuccess withObject:responseString waitUntilDone:YES];
  }
  [pool release];
 }
 return TRUE;
}


#pragma mark -
#pragma mark Synchronized methods

+(NSString *) doSynchronizedGet:(NSString *)urlString {
 NSData *returnData = [HttpHelper doSynchronizedDataGet:urlString];
 if (!returnData)
  return [NSString stringWithFormat:@"Error: %@ %@",NSLocalizedString(@"No data received from server",nil), urlString];
 
 NSString * responseString = [[[NSString alloc] initWithData: returnData encoding: NSUTF8StringEncoding] autorelease];
 return responseString;
}

+(NSData *) doSynchronizedDataGet:(NSString *)urlString {
 NSURLRequest *request = [self getURLRequestFor:urlString];
 NSHTTPURLResponse *response=nil;
 NSError *error=nil;
 NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
 
 NSString *errorString=@"";
 if (error)
  errorString = [NSString stringWithFormat:@"Error %@ '%@': %@",NSLocalizedString(@"loading page",nil), urlString, [error localizedDescription]]; 
 else if (response==nil || returnData==nil)
  errorString = [NSString stringWithFormat:@"Error - %@ %@",NSLocalizedString(@"No response from URL",nil), urlString];
 else if (response.statusCode!=200)
  errorString = [NSString stringWithFormat:@"Error - %@ %i %@ %@",NSLocalizedString(@"HTTP Error",nil), response.statusCode, NSLocalizedString(@"from URL",nil), urlString];
 
 if ([errorString length]>0)
  return [errorString dataUsingEncoding:NSUTF8StringEncoding];;
 
 if (useCookies)
  [HttpHelper getCookiesFrom:response forURL:[request URL]];
 
 return returnData;
}

+(NSString *) doSynchronizedPostTo:(NSString *)urlString withData:(NSDictionary*)data {
 NSURLRequest *request = [self buildPostRequestForURL:urlString withData:data];
 return [self doSynchronizedPostTo:urlString withRequest:request];
}
+(NSString *) doSynchronizedPostTo:(NSString *)urlString withKeys:(NSArray*)postKeys andValues:(NSArray*)postValues {
 NSURLRequest *request = [self buildRequestWithPostKeys:postKeys postValues:postValues urlString:urlString];
 return [self doSynchronizedPostTo:urlString withRequest:request];
}
+(NSString *) doSynchronizedPostTo:(NSString *)urlString withRequest:(NSURLRequest*)request {
 NSHTTPURLResponse *response=nil;
 NSError *error=nil;
 NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
 
 NSString *errorString=@"";
 if (error)
  errorString = [NSString stringWithFormat:@"Error - %@ '%@': %@",NSLocalizedString(@"HTTP Error posting to URL",nil), urlString, [error localizedDescription]]; 
 else if (response==nil || returnData==nil)
  errorString = [NSString stringWithFormat:@"Error - %@ %@",NSLocalizedString(@"No response from URL",nil), urlString];
 else if (response.statusCode!=200)
  errorString = [NSString stringWithFormat:@"Error - %@ %i %@ %@",NSLocalizedString(@"HTTP Error",nil), response.statusCode, NSLocalizedString(@"from URL",nil), urlString];
 
 if ([errorString length]>0)
  return errorString;
 
 if (useCookies)
  [HttpHelper getCookiesFrom:response forURL:[request URL]];
 
 NSString * responseString = [[[NSString alloc] initWithData: returnData encoding: NSUTF8StringEncoding] autorelease];
 
 if ([[responseString lowercaseString] hasPrefix:@"error"])
  errorString = [NSString stringWithFormat:@"Error %@ %@ %@ %@",NSLocalizedString(@"message",nil), responseString, NSLocalizedString(@"from URL",nil), urlString];
 else if ([[responseString lowercaseString] hasPrefix:@"fail"])
  errorString = [NSString stringWithFormat:@"Error - %@ '%@' %@ %@",NSLocalizedString(@"Failure message",nil), responseString, NSLocalizedString(@"when posting to URL",nil), urlString];
 
 if ([errorString length]>0)
  return errorString;
 
 return responseString;
}

+(NSString*) doSynchronizedMultipartPostTo:(NSString*)urlString withData:(NSDictionary*)data fileKeys:(NSArray*)fileKeys
{
 NSArray *keys = [data allKeys];
 NSMutableArray *values = [NSMutableArray arrayWithCapacity:[keys count]];
 for (NSString *key in keys) {
  NSString *value = [data objectForKey:key];
  [values addObject:(value ? value : @"")];
 }
 return [self doSynchronizedMultipartPostTo:urlString withKeys:keys andValues:values fileKeys:fileKeys];
}

+(NSString *) doSynchronizedMultipartPostTo:(NSString*)urlString withKeys:(NSArray*)keys andValues:(NSArray*)values fileKeys:(NSArray*)fileKeys
{
 NSURL * url = [NSURL URLWithString:urlString];
 NSURLRequestCachePolicy policy = NSURLRequestReloadIgnoringCacheData; // we never want a cache of a post response
 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:policy timeoutInterval:30.0];
 [request setHTTPMethod:@"POST"];
 
 NSString *boundary = [[NSProcessInfo processInfo] globallyUniqueString];
 [request setValue: [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary] forHTTPHeaderField:@"Content-Type"];
 
 NSMutableData *postBody =  [NSMutableData dataWithCapacity:65536];
 for (int i=0; i<[keys count]; i++) {
  NSString *key = [keys objectAtIndex:i];
  NSObject *value = [values objectAtIndex:i];

  if (value && fileKeys && [fileKeys containsObject:key]) {
   [postBody appendData: [[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
   if ([value isKindOfClass:[NSString class]]) {
    NSString *valueString = (NSString*)value;
    if ([valueString length]>0) {
     NSRange slashRange = [valueString rangeOfString:@"/" options:NSBackwardsSearch];
     NSString *fileName = slashRange.location!=NSNotFound && ![valueString hasSuffix:@"/"]
           ? [valueString substringFromIndex:slashRange.location+1]
           : valueString;
     [postBody appendData: [[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"%@\"; filename=\"%@\"\r\n", key, fileName] dataUsingEncoding:NSUTF8StringEncoding]];
     [postBody appendData: [[NSString stringWithFormat: @"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
     [postBody appendData: [NSData dataWithContentsOfMappedFile:valueString]];
    }
   }
   else if ([value isKindOfClass:[NSURL class]]) {
    NSURL *fileURL = (NSURL*)value;
    [postBody appendData: [[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"%@\"; filename=\"%@\"\r\n", key, [fileURL lastPathComponent]] dataUsingEncoding:NSUTF8StringEncoding]];
    [postBody appendData: [[NSString stringWithFormat: @"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [postBody appendData: [NSData dataWithContentsOfURL:fileURL]];
   }
   else if ([value isKindOfClass:[NSData class]]) {
    [postBody appendData: [[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"%@\"; filename=\"%@\"\r\n", key, key] dataUsingEncoding:NSUTF8StringEncoding]];
    [postBody appendData: [[NSString stringWithFormat: @"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [postBody appendData: (NSData*)value];
   }
  }
  else {
   [postBody appendData:[[NSString stringWithFormat: @"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
   [postBody appendData:[[NSString stringWithFormat: @"Content-Disposition: form-data; name=\"%@\"\r\n",key] dataUsingEncoding:NSUTF8StringEncoding]];
   [postBody appendData: [[NSString stringWithFormat: @"Content-Type: text/plain;charset=utf-8\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
   NSString *valueString = [NSString stringWithFormat: @"%@", value];
   [postBody appendData:[valueString dataUsingEncoding:NSUTF8StringEncoding]];
  }
  [postBody appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
 }
 [postBody appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
 
 NSString *msgLength = [NSString stringWithFormat:@"%d", [postBody length]];
 [request addValue: msgLength forHTTPHeaderField:@"Content-Length"];
 [request setHTTPBody:postBody];
 
 NSHTTPURLResponse *response=nil;
 NSError *error=nil;
 NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
 
 NSString *errorString=@"";
 if (error)
  errorString = [NSString stringWithFormat:@"Error - %@ '%@': %@",NSLocalizedString(@"HTTP Error posting to URL",nil), urlString, [error localizedDescription]]; 
 else if (response==nil || returnData==nil)
  errorString = [NSString stringWithFormat:@"Error - %@ %@",NSLocalizedString(@"No response from URL",nil), urlString];
 else if (response.statusCode!=200)
  errorString = [NSString stringWithFormat:@"Error - %@ %i %@ %@",NSLocalizedString(@"HTTP Error",nil), response.statusCode, NSLocalizedString(@"from URL",nil), urlString];
 
 if ([errorString length]>0)
  return errorString;
 
 NSString * responseString = [[[NSString alloc] initWithData: returnData encoding: NSUTF8StringEncoding] autorelease];
 
 if ([[responseString lowercaseString] hasPrefix:@"error"])
  errorString = [NSString stringWithFormat:@"Error %@ %@ %@ %@",NSLocalizedString(@"message",nil), responseString, NSLocalizedString(@"from URL",nil), urlString];
 else if ([[responseString lowercaseString] hasPrefix:@"fail"])
  errorString = [NSString stringWithFormat:@"Error - %@ '%@' %@ %@",NSLocalizedString(@"Failure message",nil), responseString, NSLocalizedString(@"when posting to URL",nil), urlString];
 
 if ([errorString length]>0)
  return errorString;
 
 if (useCookies)
  [HttpHelper getCookiesFrom:response forURL:[request URL]];
 return responseString;
}


@end

As you may have noticed, if your eyes for Nothing are as keen as Alice's, there hasn't been a whole lot of activity 'round here of late; that's because I've been up to my nose in paying app work, most of which I can't write about in public for obvious non-disclosure-agreement reasons. But I hope to find some pet-project time come the new year, so check back in then -

Jon