如何使用NSURLComponents将+编码到%2B中

Question

我正在使用NSURLComponents,我似乎无法获得正确编码的查询值.我需要最终的URL来表示+as %2B.

let baseUrl = NSURL(string: "http://www.example.com")    
let components = NSURLComponents(URL: baseUrl, resolvingAgainstBaseURL: true)
components.queryItems = [ NSURLQueryItem(name: "name", value: "abc+def") ]
XCTAssertEqual(components!.string!, "http://www.example.com?connectionToken=abc%2Bdef")

失败!

输出等于:

http://www.example.com?connectionToken=abc+def 

不

http://www.example.com?connectionToken=abc%2Bdef

我已经尝试了几种变化,我似乎无法将其输出%2B.

Answer 1

我从Radar 24076063得到的答案解释了为什么它的工作方式(通过一些文本清理):

"+"字符在查询组件中是合法的,因此不需要进行百分比编码.

有些系统使用'+'作为空格,并且需要'+'加号字符进行百分比编码.但是,这种两阶段编码(将加号转换为%2B然后将空格转换为加号)容易出错,因为它很容易导致编码问题.如果URL被规范化,它也会中断(URL的语法规范化包括删除所有不必要的百分比编码 - 请参阅rfc3986第6.2.2.2节).

因此,如果由于您的代码正在与之交换的服务器而需要该行为,您将自己处理额外的转换.这是一段代码,显示了您需要做的两种方式:

NSURLComponents *components = [[NSURLComponents alloc] init];
NSArray *items = [NSArray arrayWithObjects:[NSURLQueryItem queryItemWithName:@"name" value:@"Value +"], nil];
components.queryItems = items;
NSLog(@"URL queryItems: %@", [components queryItems]);
NSLog(@"URL string before: %@", [components string]);

// Replace all "+" in the percentEncodedQuery with "%2B" (a percent-encoded +) and then replace all "%20" (a percent-encoded space) with "+"
components.percentEncodedQuery = [[components.percentEncodedQuery stringByReplacingOccurrencesOfString:@"+" withString:@"%2B"] stringByReplacingOccurrencesOfString:@"%20" withString:@"+"];
NSLog(@"URL string after: %@", [components string]);

// This is the reverse if you receive a URL with a query in that form and want to parse it with queryItems
components.percentEncodedQuery = [[components.percentEncodedQuery stringByReplacingOccurrencesOfString:@"+" withString:@"%20"] stringByReplacingOccurrencesOfString:@"%2B" withString:@"+"];
NSLog(@"URL string back: %@", [components string]);
NSLog(@"URL queryItems: %@", [components queryItems]);

输出是:

URL queryItems: (
    "<NSURLQueryItem 0x100502460> {name = name, value = Value +}"
)

URL string before: ?name=Value%20+

URL string after: ?name=Value+%2B

URL string back: ?name=Value%20+

URL queryItems: (
    "<NSURLQueryItem 0x1002073e0> {name = name, value = Value +}"
)

Answer 2

正如其他答案所提到的,默认情况下,"+"不会在iOS上编码.但是,如果您的服务器要求进行编码,请按以下步骤操作:

var comps = URLComponents(url: self, resolvingAgainstBaseURL: true)
// a local var is needed to fix a swift warning about "overlapping accesses" caused by writing to the same property that's being read.
var compsCopy = comps
compsCopy?.queryItems = [URLQueryItem(name: "name", value: "abc+def")]
comps?.percentEncodedQuery = compsCopy?.percentEncodedQuery?.replacingOccurrences(of: "+", with: "%2B")

Answer 3

这是苹果的一个错误。而是使用

NSString -stringByAddingPercentEncodingWithAllowedCharacters:

和

NSCharacterSet +URLQueryAllowedCharacterSet