Parse NSURL query property
Try this ;)!
NSString *query = @"parameter=2&secondparameter=3"; // replace this with [url query];
NSArray *components = [query componentsSeparatedByString:@"&"];
NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
for (NSString *component in components) {
NSArray *subcomponents = [component componentsSeparatedByString:@"="];
[parameters setObject:[[subcomponents objectAtIndex:1] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]
forKey:[[subcomponents objectAtIndex:0] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
I had reason to write some extensions for this behavior that might come in handy. First the header:
#import <Foundation/Foundation.h>
@interface NSString (XQueryComponents)
- (NSString *)stringByDecodingURLFormat;
- (NSString *)stringByEncodingURLFormat;
- (NSMutableDictionary *)dictionaryFromQueryComponents;
@end
@interface NSURL (XQueryComponents)
- (NSMutableDictionary *)queryComponents;
@end
@interface NSDictionary (XQueryComponents)
- (NSString *)stringFromQueryComponents;
@end
These methods extend NSString, NSURL, and NSDictionary, to allow you to convert to and from query components strings and dictionary objects containing the results.
Now the related .m code:
#import "XQueryComponents.h"
@implementation NSString (XQueryComponents)
- (NSString *)stringByDecodingURLFormat
{
NSString *result = [self stringByReplacingOccurrencesOfString:@"+" withString:@" "];
result = [result stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return result;
}
- (NSString *)stringByEncodingURLFormat
{
NSString *result = [self stringByReplacingOccurrencesOfString:@" " withString:@"+"];
result = [result stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return result;
}
- (NSMutableDictionary *)dictionaryFromQueryComponents
{
NSMutableDictionary *queryComponents = [NSMutableDictionary dictionary];
for(NSString *keyValuePairString in [self componentsSeparatedByString:@"&"])
{
NSArray *keyValuePairArray = [keyValuePairString componentsSeparatedByString:@"="];
if ([keyValuePairArray count] < 2) continue; // Verify that there is at least one key, and at least one value. Ignore extra = signs
NSString *key = [[keyValuePairArray objectAtIndex:0] stringByDecodingURLFormat];
NSString *value = [[keyValuePairArray objectAtIndex:1] stringByDecodingURLFormat];
NSMutableArray *results = [queryComponents objectForKey:key]; // URL spec says that multiple values are allowed per key
if(!results) // First object
{
results = [NSMutableArray arrayWithCapacity:1];
[queryComponents setObject:results forKey:key];
}
[results addObject:value];
}
return queryComponents;
}
@end
@implementation NSURL (XQueryComponents)
- (NSMutableDictionary *)queryComponents
{
return [[self query] dictionaryFromQueryComponents];
}
@end
@implementation NSDictionary (XQueryComponents)
- (NSString *)stringFromQueryComponents
{
NSString *result = nil;
for(__strong NSString *key in [self allKeys])
{
key = [key stringByEncodingURLFormat];
NSArray *allValues = [self objectForKey:key];
if([allValues isKindOfClass:[NSArray class]])
for(__strong NSString *value in allValues)
{
value = [[value description] stringByEncodingURLFormat];
if(!result)
result = [NSString stringWithFormat:@"%@=%@",key,value];
else
result = [result stringByAppendingFormat:@"&%@=%@",key,value];
}
else {
NSString *value = [[allValues description] stringByEncodingURLFormat];
if(!result)
result = [NSString stringWithFormat:@"%@=%@",key,value];
else
result = [result stringByAppendingFormat:@"&%@=%@",key,value];
}
}
return result;
}
@end
You can use queryItems
in URLComponents
.
When you get this property’s value, the NSURLComponents class parses the query string and returns an array of NSURLQueryItem objects, each of which represents a single key-value pair, in the order in which they appear in the original query string.
Swift
let url = "http://example.com?param1=value1¶m2=param2"
let queryItems = URLComponents(string: url)?.queryItems
let param1 = queryItems?.filter({$0.name == "param1"}).first
print(param1?.value)
Alternatively, you can add an extension on URL to make things easier.
extension URL {
var queryParameters: QueryParameters { return QueryParameters(url: self) }
}
class QueryParameters {
let queryItems: [URLQueryItem]
init(url: URL?) {
queryItems = URLComponents(string: url?.absoluteString ?? "")?.queryItems ?? []
print(queryItems)
}
subscript(name: String) -> String? {
return queryItems.first(where: { $0.name == name })?.value
}
}
You can then access the parameter by its name.
let url = "http://example.com?param1=value1¶m2=param2"
print(url.queryParameters["param1"])
Something like that:
NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
for (NSString *param in [url componentsSeparatedByString:@"&"]) {
NSArray *elts = [param componentsSeparatedByString:@"="];
if([elts count] < 2) continue;
[params setObject:[elts lastObject] forKey:[elts firstObject]];
}
Note : This is sample code. All error cases are not managed.