I'm looking for a way to split a URL into its component parts so I can handle each element. Why? Because the URL is a custom scheme in an iPhone app that I want to handle specifically.
For example, if a user taps a link with the URL myapp://section/?id=123 I want to use the string after the scheme as the indication of which section to jump to in my app and then split the key/value as an indication of which subview to present to the user.
I'm guessing a Regular Expression would do the trick.
Here's an example for the NSURL class and its usage.
NSURL *url = [NSURL URLWithString:#"foo://name.com:8080/12345;param?foo=1&baa=2#fragment"];
NSLog(#"scheme: %#", [url scheme]);
NSLog(#"host: %#", [url host]);
NSLog(#"port: %#", [url port]);
NSLog(#"path: %#", [url path]);
NSLog(#"path components: %#", [url pathComponents]);
NSLog(#"parameterString: %#", [url parameterString]);
NSLog(#"query: %#", [url query]);
NSLog(#"fragment: %#", [url fragment]);
output:
scheme: foo
host: name.com
port: 8080
path: /12345
path components: (
"/",
12345
)
parameterString: param
query: foo=1&baa=2
fragment: fragment
take a look at the docs for NSURL;
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSURL_Class/Reference/Reference.html
scroll down to
Accessing the Parts of the URL
and see all that NSURL can do for you without a regex...
A regular expression is serious overkill for this. Just split first at ://, then at /.
(You could have a loook at using an NSScanner, or as Bill Dudney points out, just use NSURL ;)
Related
I saved an object to file and I am now trying to run a check on whether or not that file exists. I have confirmed the path of the file and concluded that the IF statement works when I hard code the path as a NSString, see first block. However, when I try saving the path as a NSURL, and convert it to an NSString so that fileManager can run it's method on it, it does not locate the file at the path. Anything that I am missing here?
LOCATES FILE HERE USING HARD CODE NSSTRING:
[NSKeyedArchiver archiveRootObject:employees toFile:#"/Users/xxx/Documents/employees.plist"];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *employeesPath = #"/Users/xxx/Documents/employees.plist";
if ([fileManager fileExistsAtPath:employeesPath]) {
NSLog(#"It exists! yes!");
}
else {
NSLog(#"Doesn't exist, sorry bud");
}
DOES NOT LOCATE FILE USING NSURL:
[NSKeyedArchiver archiveRootObject:employees toFile:#"/Users/xxx/Documents/employees.plist"];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *employeesPath = [NSURL fileURLWithPath:#"/Users/xxx/Documents/employees.plist"];
NSString *employeesString = [employeesPath absoluteString];
if ([fileManager fileExistsAtPath:employeesString]) {
NSLog(#"It exists! yes!");
}
else {
NSLog(#"Doesn't exist, sorry bud");
}
EDIT
-- if I wanted to use the NSURL method, I could by making a function to store the path into a NSString the proper way. This ended up working:
NSString* getPropertyListPath() {
NSURL *documentDir = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
NSURL *plist = [documentDir URLByAppendingPathComponent:#"employees.plist"];
return plist.path;
}
You are correct to use NSURL, giuseppe, instead of string literals.
NSURL is more compatible and robust than a string literal. NSURL types will give you access to more methods and functionality.
The trick that you stumbled into is that you needed the file path without the "scheme" or "domain" included in the format.
You are correct to call the path method on your NSURL object to retrieve the correct path format for what you need. The path method only returns the path component to the NSURL address path. It doesn't return the scheme or domain components.
NSString *correctPathFormat = [yourNsurlObject path];
For Example:
If I have a file in the following directory path:
NSString* myDirPath = #"/Users/yourUserName/imageFolder";
and load this into a NSURL object:
NSURL *nsurlDirPath = [NSURL fileURLWithPath:myDirPath];
then append the file name and file type:
NSURL *nsurlFilePath = [nsurlDirPath URLByAppendingPathComponent:#"employee.plist"];
If you call the [nsurlFilePath absoluteString] method you will get an NSString value in the format of "scheme://domain/path"
NSString *retrievePath = [nsurlFilePath absoluteString];
NSLog(#"%#",retrievePath);
This logs out:
file:///Users/yourUserName/imageFolder/employee.plist
Special Note: This is the equivalent to the file path:
file://localhost/Users/yourUserName/imageFolder/employee.plist
The "localhost" is just omitted because this is by default implied, so that is why you see the tripple "///" in "file:///Users/...".
"localhost" is an alias that refers to the local device's ip address, or in other words, the device the code is running on.
Finally, to get the correct path format you need you would run the 'path' method on the NSURL object, which takes us back to the answer at the very beginning of my response:
NSString *correctPathFormat = [nsurlFilePath path];
This logs out the correct "path" component, minus the "scheme" & "domain":
/Users/yourUserName/imageFolder/employee.plist
Further Explanation:
NSURLS have three parts:
scheme : [http, https, ftp, file]
domain : [www.stackoverflow.com, localhost, ipAddress]
path : [/questions/26663573/, /Users/youUserName/subDirName]
scheme | domain | path
file://localhost/Users/youruserName/file.txt
Don't use a NSURL as a file path intermediary.
NSURL *employeesPath = [NSURL fileURLWithPath:#"/Users/xxx/Documents/employees.plist"];
NSString *employeesString = [employeesPath absoluteString];
NSLog(#"employeesString: %#", 'employeesString');
Output:
employeesString: 'file:///Users/xxx/Documents/employees.plist'
Which is clearly not a file path.
I think I don't understand the concept of "baseURL". This:
NSLog(#"BASE URL: %# %#", [NSURL URLWithString:#"http://www.google.es"], [[NSURL URLWithString:#"http://www.google.es"] baseURL]);
Prints this:
BASE URL: http://www.google.es (null)
And of course, in the Apple docs I read this:
Return Value
The base URL of the receiver. If the receiver is an absolute URL, returns nil.
I'd like to get from this example URL:
https://www.google.es/search?q=uiviewcontroller&aq=f&oq=uiviewcontroller&sourceid=chrome&ie=UTF-8
This base URL
https://www.google.es
My question is simple. Is there any cleaner way of getting the actual base URL without concatenating the scheme and the hostname? I mean, what's the purpose of base URL then?
-baseURL is a concept purely of NSURL/CFURL rather than URLs in general. If you did this:
[NSURL URLWithString:#"search?q=uiviewcontroller"
relativeToURL:[NSURL URLWithString:#"https://www.google.es/"]];
then baseURL would be https://www.google.es/. In short, baseURL is only populated if the NSURL is created using a method that explicitly passes in a base URL. The main purpose of this feature is to handle relative URL strings such as might be found in the source of a typical web page.
What you're after instead, is to take an arbitrary URL and strip it back to just the host portion. The easiest way I know to do this is a little cunning:
NSURL *aURL = [NSURL URLWithString:#"https://www.google.es/search?q=uiviewcontroller"];
NSURL *hostURL = [[NSURL URLWithString:#"/" relativeToURL:aURL] absoluteURL];
This will give a hostURL of https://www.google.es/
I have such a method published as -[NSURL ks_hostURL] as part of KSFileUtilities (scroll down the readme to find it documented)
If you want purely the host and not anything like scheme/port etc. then -[NSURL host] is your method.
Docs for BaseURL.
baseURL
Returns the base URL of the receiver.
- (NSURL *)baseURL
Return Value
The base URL of the receiver. If the receiver is an absolute URL, returns nil.
Availability
Available in iOS 2.0 and later.
Declared In
NSURL.h
Seems it only works for relative URLs.
You could possibly use ...
NSArray *pathComponents = [url pathComponents]
and then take the bits you want.
Or try...
NSString *host = [url host];
you can use host method
NSURL *url = [[NSURL alloc] initWithString:#"http://www.hello.com"];
NSLog(#"Host:%#", url.host);
result:
Host:www.hello.com
It might be just me, but when I think further about the double-URL solution, it sounds like something that could stop working between OS updates. So I decided to share yet another solution, definitely not beautiful either, but I find it more readable by the general public since it doesn't rely on any hidden specificity of the framework.
if let path = URL(string: resourceURI)?.path {
let baseURL = URL(string: resourceURI.replacingOccurrences(of: path, with: ""))
...
}
Here's a quick, easy, and safe way to fetch the base URL:
NSError *regexError = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"http://.*/" options:NSRegularExpressionCaseInsensitive error:®exError];
if (regexError) {
NSLog(#"regexError: %#", regexError);
return nil;
}
NSTextCheckingResult *match = [regex firstMatchInString:url.absoluteString options:0 range:NSMakeRange(0, url.absoluteString.length)];
NSString *baseURL = [url.absoluteString substringWithRange:match.range];
I have looked at NSWorkSpace and NSFileManager but I can't find out the methods that I'm looking for.
I have a saved url (getting from NSSavePanel).
ie. this url can be /Users/Josh/Some Folders/file.txt or
/Volumes/My USB Key Name/file.txt
So can I use this url to find out the displayed volume name?
[[NSWorkspace sharedWorkspace] mountedLocalVolumePaths] can list all the local volume name, but it's Deprecated in os x 10.7
found the answer:
NSURL *savedPath = [NSURL fileURLWithPath:[saveURL.path stringByDeletingLastPathComponent]];
NSError *error;
NSString *volumeName;
[savedPath getResourceValue:&volumeName forKey:NSURLVolumeNameKey error:&error];
NSLog(#"volume name: %# url: %#", volumeName, savedPath);
I am trying to get HTML files from the web, using stringWithContentsOfURL:. My problem is, sometimes it works but sometimes it doesn't. For example, I tried:
NSString *string = [NSString stringWithContentsOfURL:
[NSURL URLWithString:#"http://www.google.com/"]
encoding:encoding1
error:nil];
NSLog(#"html = %#",string);
This works fine, but when I replace the URL with #"http://www.youtube.com/" then I only get "NULL". Is there anyone that knows what's going on? Is it because of YouTube having some sort of protection?
Google's home page uses ISO-8859-1 encoding (aka "Latin-1", or NSISOLatin1StringEncoding). YouTube uses UTF-8 (NSUTF8StringEncoding), and the encoding you've specified with your encoding1 variable has to match the web page in question.
If you just want the web page and don't really care what encoding it's in, try this:
NSStringEncoding encoding;
NSError *error;
NSString *string = [NSString stringWithContentsOfURL:
[NSURL URLWithString:#"http://www.google.com/"]
usedEncoding:&encoding
error:&error];
NSLog(#"html = %#",string);
This method will tell you what the encoding was (by writing it to the encoding variable), but you can just throw that away and focus on the string.
I've looked at quite a few of the related questions and cannot find a similar problem or a solution so my apologies if there is a duplicate out there somewhere.
Anyway, I'm trying to generate a file's NSURL to use with an NSXMLDocument. I have the following components:
const NSString * PROJECT_DIR = #"~/SP\\ BB/";
const NSString * STRINGS_FILE = #"Localizable.strings";
and construct the URL like so:
NSURL * stringsURL = [NSURL fileURLWithPath:[[NSString stringWithFormat:#"%#%#",PROJECT_DIR,STRINGS_FILE] stringByExpandingTildeInPath]];
however, the resulting path in the NSURL is:
file://localhost/Users/timothyborrowdale/SP2B/Localizable.strings
I have tried changing the PROJECT_DIR to
#"~/SP BB/"
#"~/SP\\\\ BB/" (changes to SP엀2B)
#"~/SP%20BB/"
#"~/SP\%20BB/"
with the same problem. I also tried typing out the file url completely and using [NSURL URLWithString:]
I have also tried using stringByAddingPercentEscapesUsingEncoding with both NSUTF8Encoding and NSASCCIEncoding and these have the same issue.
The NSString displays properly before being passed to NSURL or stringByAddingPercentEscapesUsingEncoding but has the problem once outputted from either.
Try this:
NSString *fnam = [#"Localizable" stringByAppendingPathExtension:#"strings"];
NSArray *parts = [NSArray arrayWithPathComponents:#"~", #"SP BB", fnam, (void *)nil];
NSString *path = [[NSString pathWithComponents:parts] stringByStandardizingPath];
NSURL *furl = [NSURL fileURLWithPath:path];
Foundation has a host of platform-independent, path-related methods. Prefer those over hard-coding path extension separators (often ".") and path component separators (often "/" or "\").
Try abandoning stringWithFormat: (never the right answer for stapling paths together) and stringByExpandingTildeInPath and using NSHomeDirectory() and stringByAppendingPathComponent: instead.
#"~/SP\\ BB/" (changes to SP엀2B)
How did you arrive at that conclusion?