objective-c - Creating URL query parameters from NSDictionary objects in ObjectiveC

Question

With all the URL-handling objects lying around in the standard Cocoa libraries (NSURL, NSMutableURL, NSMutableURLRequest, etc), I know I must be overlooking an easy way to programmatically compose a GET request.

Currently I'm manually appending "?" followed by name value pairs joined by "&", but all of my name and value pairs need to be manually encoded so NSMutableURLRequest doesn't fail entirely when it tries to connect to the URL.

This feels like something I should be able to use a pre-baked API for.... is there anything out of the box to append an NSDictionary of query parameters to an NSURL? Is there another way I should approach this?

score 133 · Accepted Answer

在 iOS8 和 OS X 10.10 中引入的是NSURLQueryItem，可用于构建查询。从NSURLQueryItem上的文档：

NSURLQueryItem 对象表示 URL 查询部分中项目的单个名称/值对。您可以使用带有 NSURLComponents 对象的 queryItems 属性的查询项。

要创建一个使用指定的初始化程序queryItemWithName:value:，然后将它们添加NSURLComponents到生成一个NSURL. 例如：

NSURLComponents *components = [NSURLComponents componentsWithString:@"http://stackoverflow.com"];
NSURLQueryItem *search = [NSURLQueryItem queryItemWithName:@"q" value:@"ios"];
NSURLQueryItem *count = [NSURLQueryItem queryItemWithName:@"count" value:@"10"];
components.queryItems = @[ search, count ];
NSURL *url = components.URL; // http://stackoverflow.com?q=ios&count=10

请注意，问号和 & 号是自动处理的。NSURL从参数字典创建一个非常简单：

NSDictionary *queryDictionary = @{ @"q": @"ios", @"count": @"10" };
NSMutableArray *queryItems = [NSMutableArray array];
for (NSString *key in queryDictionary) {
    [queryItems addObject:[NSURLQueryItem queryItemWithName:key value:queryDictionary[key]]];
}
components.queryItems = queryItems;

我还写了一篇关于如何使用和构建 URLNSURLComponents的博文NSURLQueryItems。

score 47 · Accepted Answer

You can create a category for NSDictionary to do this -- there isn't a standard way in the Cocoa library that I could find either. The code that I use looks like this:

// file "NSDictionary+UrlEncoding.h"
#import <cocoa/cocoa.h>

@interface NSDictionary (UrlEncoding)

-(NSString*) urlEncodedString;

@end

with this implementation:

// file "NSDictionary+UrlEncoding.m"
#import "NSDictionary+UrlEncoding.h"

// helper function: get the string form of any object
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);
  return [string stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding];
}

@implementation NSDictionary (UrlEncoding)

-(NSString*) urlEncodedString {
  NSMutableArray *parts = [NSMutableArray array];
  for (id key in self) {
    id value = [self objectForKey: key];
    NSString *part = [NSString stringWithFormat: @"%@=%@", urlEncode(key), urlEncode(value)];
    [parts addObject: part];
  }
  return [parts componentsJoinedByString: @"&"];
}

@end

I think the code's pretty straightforward, but I discuss it in some more detail at http://blog.ablepear.com/2008/12/urlencoding-category-for-nsdictionary.html.

score 30 · Accepted Answer

我想使用 Chris 的答案，但它不是为自动引用计数(ARC) 编写的，所以我更新了它。我想我会粘贴我的解决方案，以防其他人遇到同样的问题。 注意：在适当的地方替换self为实例或类名。

+(NSString*)urlEscapeString:(NSString *)unencodedString 
{
    CFStringRef originalStringRef = (__bridge_retained CFStringRef)unencodedString;
    NSString *s = (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,originalStringRef, NULL, (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ", kCFStringEncodingUTF8);
    CFRelease(originalStringRef);
    return s;
}


+(NSString*)addQueryStringToUrlString:(NSString *)urlString withDictionary:(NSDictionary *)dictionary
{
    NSMutableString *urlWithQuerystring = [[NSMutableString alloc] initWithString:urlString];

    for (id key in dictionary) {
        NSString *keyString = [key description];
        NSString *valueString = [[dictionary objectForKey:key] description];

        if ([urlWithQuerystring rangeOfString:@"?"].location == NSNotFound) {
            [urlWithQuerystring appendFormat:@"?%@=%@", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
        } else {
            [urlWithQuerystring appendFormat:@"&%@=%@", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
        }
    }
    return urlWithQuerystring;
}

score 22 · Accepted Answer

如果值是字符串，则其他答案效果很好，但是如果值是字典或数组，则此代码将处理该问题。

需要注意的是，没有通过查询字符串传递数组/字典的标准方法，但 PHP 可以很好地处理此输出

-(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 = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                                              (CFStringRef)[value objectForKey:subKey],
                                                                                              NULL,
                                                                                              (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                                                              kCFStringEncodingUTF8);
                [pairs addObject:[NSString stringWithFormat:@"%@[%@]=%@", key, subKey, escaped_value]];
            }
        } else if ([value isKindOfClass:[NSArray class]]) {
            for (NSString *subValue in value) {
                NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                                              (CFStringRef)subValue,
                                                                                              NULL,
                                                                                              (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                                                              kCFStringEncodingUTF8);
                [pairs addObject:[NSString stringWithFormat:@"%@[]=%@", key, escaped_value]];
            }
        } else {
            NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                                          (CFStringRef)[params objectForKey:key],
                                                                                          NULL,
                                                                                          (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                                                          kCFStringEncodingUTF8);
            [pairs addObject:[NSString stringWithFormat:@"%@=%@", key, escaped_value]];
            [escaped_value release];
        }
    }
    return [pairs componentsJoinedByString:@"&"];
}

例子

[foo] => bar
[translations] => 
        {
            [one] => uno
            [two] => dos
            [three] => tres
        }

foo=bar&translations[one]=uno&translations[two]=dos&translations[three]=tres

[foo] => bar
[translations] => 
        {
            uno
            dos
            tres
        }

foo=bar&translations[]=uno&translations[]=dos&translations[]=tres

score 8 · Accepted Answer

我重构并转换为 AlBeebe 的 ARC 答案

- (NSString *)serializeParams:(NSDictionary *)params {
    NSMutableArray *pairs = NSMutableArray.array;
    for (NSString *key in params.keyEnumerator) {
        id value = params[key];
        if ([value isKindOfClass:[NSDictionary class]])
            for (NSString *subKey in value)
                [pairs addObject:[NSString stringWithFormat:@"%@[%@]=%@", key, subKey, [self escapeValueForURLParameter:[value objectForKey:subKey]]]];

        else if ([value isKindOfClass:[NSArray class]])
            for (NSString *subValue in value)
            [pairs addObject:[NSString stringWithFormat:@"%@[]=%@", key, [self escapeValueForURLParameter:subValue]]];

        else
            [pairs addObject:[NSString stringWithFormat:@"%@=%@", key, [self escapeValueForURLParameter:value]]];

}
return [pairs componentsJoinedByString:@"&"];

}

- (NSString *)escapeValueForURLParameter:(NSString *)valueToEscape {
     return (__bridge_transfer NSString *) CFURLCreateStringByAddingPercentEscapes(NULL, (__bridge CFStringRef) valueToEscape,
             NULL, (CFStringRef) @"!*'();:@&=+$,/?%#[]", kCFStringEncodingUTF8);
}

score 6 · Accepted Answer

如果您已经在使用AFNetworking（就像我一样），您可以使用它的类AFHTTPRequestSerializer来创建所需的NSURLRequest.

[[AFHTTPRequestSerializer serializer] requestWithMethod:@"GET" URLString:@"YOUR_URL" parameters:@{PARAMS} error:nil];

如果您只需要工作的 URL，请使用NSURLRequest.URL.

score 3 · Accepted Answer

这是Swift (iOS8+) 中的一个简单示例：

private let kSNStockInfoFetchRequestPath: String = "http://dev.markitondemand.com/Api/v2/Quote/json"

private func SNStockInfoFetchRequestURL(symbol:String) -> NSURL? {
  if let components = NSURLComponents(string:kSNStockInfoFetchRequestPath) {
    components.queryItems = [NSURLQueryItem(name:"symbol", value:symbol)]
    return components.URL
  }
  return nil
}

score 3 · Accepted Answer

我接受了 Joel 的使用建议URLQueryItems并变成了 Swift Extension (Swift 3)

extension URL
{
    /// Creates an NSURL with url-encoded parameters.
    init?(string : String, parameters : [String : String])
    {
        guard var components = URLComponents(string: string) else { return nil }

        components.queryItems = parameters.map { return URLQueryItem(name: $0, value: $1) }

        guard let url = components.url else { return nil }

        // Kinda redundant, but we need to call init.
        self.init(string: url.absoluteString)
    }
}

（该self.init方法有点俗气，但没有NSURL带有组件的初始化）

可以用作

URL(string: "http://www.google.com/", parameters: ["q" : "search me"])

score 2 · Accepted Answer

-(NSString*)encodeDictionary:(NSDictionary*)dictionary{
    NSMutableString *bodyData = [[NSMutableString alloc]init];
    int i = 0;
    for (NSString *key in dictionary.allKeys) {
        i++;
        [bodyData appendFormat:@"%@=",key];
        NSString *value = [dictionary valueForKey:key];
        NSString *newString = [value stringByReplacingOccurrencesOfString:@" " withString:@"+"];
        [bodyData appendString:newString];
        if (i < dictionary.allKeys.count) {
            [bodyData appendString:@"&"];
        }
    }
    return bodyData;
}

score 2 · Accepted Answer

我有另一个解决方案：

http://splinter.com.au/build-a-url-query-string-in-obj-c-from-a-dict

+(NSString*)urlEscape:(NSString *)unencodedString {
    NSString *s = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
        (CFStringRef)unencodedString,
        NULL,
        (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
        kCFStringEncodingUTF8);
    return [s autorelease]; // Due to the 'create rule' we own the above and must autorelease it
}

// Put a query string onto the end of a url
+(NSString*)addQueryStringToUrl:(NSString *)url params:(NSDictionary *)params {
    NSMutableString *urlWithQuerystring = [[[NSMutableString alloc] initWithString:url] autorelease];
    // Convert the params into a query string
    if (params) {
        for(id key in params) {
            NSString *sKey = [key description];
            NSString *sVal = [[params objectForKey:key] description];
            // Do we need to add ?k=v or &k=v ?
            if ([urlWithQuerystring rangeOfString:@"?"].location==NSNotFound) {
                [urlWithQuerystring appendFormat:@"?%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
            } else {
                [urlWithQuerystring appendFormat:@"&%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
            }
        }
    }
    return urlWithQuerystring;
}

然后你可以像这样使用它：

NSDictionary *params = @{@"username":@"jim", @"password":@"abc123"};

NSString *urlWithQuerystring = [self addQueryStringToUrl:@"https://myapp.com/login" params:params];

score 1 · Accepted Answer

Simple way of converting NSDictionary to url query string in Objective-c

Ex: first_name=Steve&middle_name=Gates&last_name=Jobs&address=Palo Alto, California

    NSDictionary *sampleDictionary = @{@"first_name"         : @"Steve",
                                     @"middle_name"          : @"Gates",
                                     @"last_name"            : @"Jobs",
                                     @"address"              : @"Palo Alto, California"};

    NSMutableString *resultString = [NSMutableString string];
            for (NSString* key in [sampleDictionary allKeys]){
                if ([resultString length]>0)
                    [resultString appendString:@"&"];
                [resultString appendFormat:@"%@=%@", key, [sampleDictionary objectForKey:key]];
            }
NSLog(@"QueryString: %@", resultString);

Hope will help :)

score 1 · Accepted Answer

另一个解决方案，如果您使用RestKitRKURLEncodedSerialization ，那么调用的函数RKURLEncodedStringFromDictionaryWithEncoding正是您想要的。

score 0 · Accepted Answer

如果你已经在使用AFNetwork，你可以使用他们内置的序列化器来生成一个编码的 URL；

NSString *baseURL = @"https://api.app.com/parse";
NSDictionary *mutableParameters = [[NSMutableDictionary alloc] initWithObjectsAndKeys:@"true",@"option1", data, @"option2", token, @"token", @"3.0", @"app", nil];
NSURLRequest *request = [[AFHTTPRequestSerializer serializer] requestWithMethod:@"GET" URLString:baseURL parameters:mutableParameters error:nil];
NSString *urlPath = request.URL.absoluteString;
NSLog(@"%@", urlPath); // https://api.app.com/parse?option1=true&option2=datavalue&token=200%3ATEST%3AENCODE ....

笔记; 这是对上述答案的扩展。编辑队列已满，因此无法添加到现有答案中。

objective-c - Creating URL query parameters from NSDictionary objects in ObjectiveC

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