由于所有的URL处理对象都位于标准的Cocoa库(NSURL,NSMutableURL,NSMutableURLRequest等)中,我知道我必须忽略一种以编程方式编写GET请求的简单方法.
目前我手动追加"？" 后跟由"&"连接的名称值对,但我的所有名称和值对都需要手动编码,因此NSMutableURLRequest在尝试连接到URL时不会完全失败.
这感觉就像我应该能够使用预先出炉的API ......是否有任何开箱即可将查询参数的NSDictionary附加到NSURL？我还有另一种方法吗？
在iOS8和OS X 10.10中引入NSURLQueryItem,可用于构建查询.从NSURLQueryItem上的文档:
NSURLQueryItem对象表示URL的查询部分中的项的单个名称/值对.您将查询项与NSURLComponents对象的queryItems属性一起使用.
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&符号会自动处理.NSURL从参数字典创建一个简单如下:
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用NSURLComponents和构建URL 的博客文章NSURLQueryItems.
您可以创建一个类别NSDictionary来执行此操作 - 在Cocoa库中没有我可以找到的标准方法.我使用的代码如下所示:
// file "NSDictionary+UrlEncoding.h" #import@interface NSDictionary (UrlEncoding) -(NSString*) urlEncodedString; @end
有了这个实现:
// 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
我认为代码非常简单,但我在http://blog.ablepear.com/2008/12/urlencoding-category-for-nsdictionary.html上更详细地讨论了它.
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.我以为我会粘贴我的解决方案以防其他人有同样的问题. 注意:self在适当的地方替换实例或类名.
+(NSString*)urlEscapeString:(NSString *)unencodedString
{
CFStringRef originalStringRef = (__bridge_retained CFStringRef)unencodedString;
NSString *s = (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,originalStringRef, NULL, (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ", kCFStringEncodingUTF8);
CFRelease(originalStringRef);
return s;
}
+(NSString*)addQueryStringToUrlString:(NSString *)urlString withDictionary:(NSDictionary *)dictionary
{
NSMutableString *urlWithQuerystring = [[NSMutableString alloc] initWithString:urlString];
for (id key in dictionary) {
NSString *keyString = [key description];
NSString *valueString = [[dictionary objectForKey:key] description];
if ([urlWithQuerystring rangeOfString:@"?"].location == NSNotFound) {
[urlWithQuerystring appendFormat:@"?%@=%@", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
} else {
[urlWithQuerystring appendFormat:@"&%@=%@", [self urlEscapeString:keyString], [self urlEscapeString:valueString]];
}
}
return urlWithQuerystring;
}
如果值是字符串,则其他答案很有效,但是如果值是字典或数组,则此代码将处理该字符串.
重要的是要注意,没有通过查询字符串传递数组/字典的标准方法,但PHP处理此输出就好了
-(NSString *)serializeParams:(NSDictionary *)params {
/*
Convert an NSDictionary to a query string
*/
NSMutableArray* pairs = [NSMutableArray array];
for (NSString* key in [params keyEnumerator]) {
id value = [params objectForKey:key];
if ([value isKindOfClass:[NSDictionary class]]) {
for (NSString *subKey in value) {
NSString* escaped_value = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
(CFStringRef)[value objectForKey:subKey],
NULL,
(CFStringRef)@"!*'();:@&=+$,/?%#[]",
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
}
富=酒吧和翻译[酮] = UNO&翻译[2] =&DOS翻译[3] = TRES
[foo] => bar
[translations] =>
{
uno
dos
tres
}
富=酒吧和翻译[] = UNO&翻译[] = DOS&翻译[] = TRES
我重构并转换为AlBeebe的ARC回答
- (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);
}
如果您已经在使用AFNetworking(就像我的情况一样),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.
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