i want to check if a URL is accessible or correct, how can i send a request and see of it is available?
Simply rely on Foundation Framework..
From NSURL documentation
URLWithString: Creates and returns an NSURL object initialized with a
provided string.
+ (id)URLWithString:(NSString *)URLString
Parameters
URLString : The string with which to initialize the NSURL object. Must
conform to RFC 2396. This method parses URLString according to RFCs
1738 and 1808.
Return Value
An NSURL object initialized with URLString. If the string was
malformed, returns nil.
This will validate if the URL does not confirm to specified standards..
Next case , to find out whether URL is accessible, Implement NSURLConnectionDelegate, override
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
And try to connect to specified URL..If URL is inaccessible above given delegate will fire and see error case there..
Related
I'm trying to do a fairly basic HTTP PUT using RestKit. I don't want to put the entire object, since the API call was designed to accept a single query parameter and just update that field. I've tried two approaches so far, both unsuccessful.
URL to post to: https://myserver/api/users/{userId}
Query string parameter: verificationCode=
Example usage: PUT https://myserver/api/users/101?verificationCode=646133
Approach #1: Put the query parameter in a RKParams object and make the PUT call with those params.
NSString *putUrl = [NSString stringWithFormat:#"/api/users/%i", [APIUserInfo sharedAPIUserInfo].apiUserIdx];
NSLog(#"the PUT url is %#", putUrl);
// Send a PUT to a remote resource. The dictionary will be transparently
// converted into a URL encoded representation and sent along as the request body
NSDictionary* paramsDict = [NSDictionary dictionaryWithObject:[_verificationCode text] forKey:#"verificationCode"];
// Convert the NS Dictionary into Params
RKParams *params = [RKParams paramsWithDictionary:paramsDict];
[[RKClient sharedClient] put:putUrl params:params delegate:self];
Approach #2: Build the entire url and try a PUT with params set to nil.
NSString *putUrl = [NSString stringWithFormat:#"/api/users/%i?verificationCode=%#", [APIUserInfo sharedAPIUserInfo].apiUserIdx, [_verificationCode text]];
NSLog(#"the PUT url is %#", putUrl);
[[RKClient sharedClient] put:putUrl params:nil delegate:self];
Neither approach is working for me. The first fails saying "RestKit was asked to retransmit a new body stream for a request. Possible connection error or authentication challenge?" then runs for about 10 seconds and times out. The second approach fails saying HTTP Status 405 - Method Not Allowed.
Can anyone point out where I'm going wrong, or provide me with a simple PUT example using RestKit? Most of the examples I've found at there are putting the entire object which I don't want to do in this case.
UPDATE:
Approach #2 worked well once I got a few things sorted out on the server side. Final solution:
NSString *putUrl = [NSString stringWithFormat:#"/api/users/verify/%i?verificationCode=%#", [APIUserInfo sharedAPIUserInfo].apiUserIdx, [_verificationCode text]];
NSLog(#"the PUT url is %#", putUrl);
[[RKClient sharedClient] put:putUrl params:nil delegate:self];
the HTTP PUT method is disabled on your webserver. It is by default on all webserver for security reasons.
HTTP Status 405 - Method Not Allowed.
How to access the (POST)data sent with the request from the requestFailed/requestFinished function.
- (void) abc {
NSString *postString = #"john";
NSURL *url = [NSURL URLWithString:#"http://abc.com"];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setPostValue:postString forKey:#"name"];
[request setDelegate:self];
[request startAsynchronus];
}
- (void) requestFinished:(ASIHTTPRequest *)request
{
// Question is whether the request holds the sent post values.
// If it holds. how can we access them.
// i tried using [request valueForKey:#"name"];
// but it won't work.
}
Handling success and failure for multiple requests in delegate methods
If you need to handle success and failure on many different types of
request, you have several options:
If your requests are all of the same broad type, but you want to
distinguish between them, you can set the userInfo NSDictionary
property of each request with your own custom data that you can read
in your finished / failed delegate methods. For simpler cases, you can
set the request’s tag property instead. Both of these properties are
for your own use, and are not sent to the server.
If you need to handle success and failure in a completely different way for each
request, set a different setDidFinishSelector / setDidFailSelector for
each request For more complex situations, or where you want to parse
the response in the background, create a minimal subclass of
ASIHTTPRequest for each type of request, and override requestFinished:
and failWithError:.
That provided me a good solution to handle different requests.
You could try this -
- (void)requestFinished:(ASIHTTPRequest *)request {
NSLog(#"Response %d ==> %#", request.responseStatusCode, [request responseString]);
}
You can also handle other methods if you choose, such as:
- (void)requestStarted:(ASIHTTPRequest *)request;
- (void)requestFailed:(ASIHTTPRequest *)request;
The docs are located at http://allseeing-i.com/ASIHTTPRequest/ and are fantastic.
You can cast your request into a ASIFormDataRequest:
if ([request isKindOfClass:[ASIFormDataRequest class]]) {
ASIFormDataRequest *requestWithPostDatas = (ASIFormDataRequest *)request;
NSArray *myPostData = [requestWithPostDatas getPostData];
}
You will also have to make "postData" accessible with a "getPostData" public function in ASIFormDataRequest.
My user enters a recipients address (Street address not email). I need to verify it with the USPS so I know that it is actually an address.
I am digging through their API right now and I think I understand it but I'm not exactly sure how to go about it with objective-c.
So pretty much it works like so:
I have to create an XML request that contains the recipient name, address, and zip code.
I have to post that to their server
They respond with an XML response
Here is an example of what one of their constructed XML request looks like:
http://SERVERNAME/ShippingAPITest.dll?API=Verify&XML=<AddressValidateRequest% 20USERID="xxxxxxx"><Address ID="0"><Address1></Address1>
<Address2>6406 Ivy Lane</Address2><City>Greenbelt</City><State>MD</State> <Zip5></Zip5><Zip4></Zip4></Address></AddressValidateRequest>
A bit garbled but broken down:
http://SERVERNAME/ShippingAPITest.dll?API=Verify&XML=
<AddressValidateRequest% 20USERID="xxxxxxx">
<Address ID="0">
<Address1></Address1>
<Address2>6406 Ivy Lane</Address2>
<City>Greenbelt</City>
<State>MD</State>
<Zip5></Zip5>
<Zip4></Zip4>
</Address>
</AddressValidateRequest>
My first idea seems obvious but there maybe a better way to go about it. Since the XML feed short, should I go about construction by simple doing something along the lines of:
NSString *request = [NSString stringWithFormat:#"......"]
Where it is filled in and formatted along the lines posted above.
The second question is how to go about correctly sending this to the server?
I simply create a NSURL request and with the URL as the constructed XML string?
Here what I have but I keep getting that the URL was constructed wrong:
- (void)verifyAddress:(Recipient*)_recipient {
NSURL *_url = [NSURL URLWithString:#"http://testing.shippingapis.com/ShippingAPITest.dll?API=Verify&XML=<AddressValidateRequest%20USERID=\"********\"><Address ID=\"0\"><Address1></Address1><Address2>6406 Ivy Lane</Address2><City>Greenbelt</City><State>MD</State><Zip5></Zip5><Zip4></Zip4></Address></AddressValidateRequest>"];
// Create the request.
NSURLRequest *theRequest=[NSURLRequest requestWithURL:_url
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
// create the connection with the request
// and start loading the data
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
// Create the NSMutableData to hold the received data.
// receivedData is an instance variable declared elsewhere.
receivedData = [NSMutableData data];
NSString* newStr = [[NSString alloc] initWithData:receivedData
encoding:NSUTF8StringEncoding];
NSLog(#"the response '%#'", newStr);
} else {
// Inform the user that the connection failed.
NSLog(#"error");
}
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
// This method is called when the server has determined that it
// has enough information to create the NSURLResponse.
// It can be called multiple times, for example in the case of a
// redirect, so each time we reset the data.
// receivedData is an instance variable declared elsewhere.
[receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// Append the new data to receivedData.
// receivedData is an instance variable declared elsewhere.
[receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error
{
// inform the user
NSLog(#"Connection failed! Error - %# %#",
[error localizedDescription],
[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString* newStr = [[NSString alloc] initWithData:receivedData
encoding:NSUTF8StringEncoding];
NSLog(#"the response '%#'", newStr);
// do something with the data
// receivedData is declared as a method instance elsewhere
NSLog(#"Succeeded! Received %d bytes of data",[receivedData length]);
}
I get the following error:
Connection failed! Error - bad URL (null)
My only question now is, am I doing everything ok as far as NSURLConnection goes? I can play around with the URL, I just want to make sure my implementation is ok so Im not running around in circles. :P
You have % 20 in your URL. It should be %20 (no space).
There may be other problems, but that was one was easy to spot. If you are getting an error message, you need to edit your question and paste in the exact error message.
Also, you might consider using Apple's NSURLRequest and NSURLConnection classes, because more people are likely to be familiar with them so it may be easier for you to find help.
Cory, I work in the address validation industry (for SmartyStreets, where what you're trying to do is our specialty in fact) and have seen a lot of similar issues to yours.
We actually used to support an XML-endpoint for our address verification API (LiveAddress). Last year we deprecated it and deployed a new JSON format because the XML was clunky to use and had a lot of problems when it's actually just a simple task (for you, the developer).
So a few things to keep in mind... and while Rob's answer is programmatically comprehensive, these are important to consider also:
The USPS is the official source of addresses for the USA, but its core domain is not providing API service. Especially with recent financial troubles, I suspect that support and maintenance of the API will wane over time.
The License Agreement for the API you're using is quite restrictive. For example:
User agrees to use the USPS Web site, APIs and USPS data to facilitate USPS shipping transactions only. [27 Jan 2012]
Meaning, if you're shipping mail or packages via the USPS by using their API, it's fine, but for any other purpose it's not allowed and it violates the TOS.
I see you're developing for iOS. There's a great JSON library for that called TouchJSON that, in my opinion, is easier to use than XML formats in Objective-C.
While the USPS service does work, they CASS-certify private entities to provide their data at a better value (more specialty, experience, features, etc).
These and other maladies can be remedied by service from a third-party vendor. More details and reasons are documented here. Which provider you choose is up to you, but I'll be happy to personally answer any other address-validation-related questions.
I'm trying to use this string inside this NSURL however I don't think its right and in turn giving me an ASI HTTP request failed error.
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:#"https://furious-ice-356.heroku.com/places/%#/reviews.xml",self.identifier]];
self.identifier returns (in most cases) an object of the type id. You cannot cast this object to a NSString*.
The only exception is the in 10.7 newly introduced identifier property of NSString* in the NSUserInterfaceItemIdentification protocol.
Can you elaborate your question so we can see what type self has?
how to get a web page content from a console application or library? I mean, no UI elemens.
This is what I mean in python
from urllib import urlopen
str = urlopen("http://www.google.com").read()
or php
$str = file_get_contents('http://www.google.com');
or c#
using System.Net;
WebClient client = new WebClient();
string str = client.DownloadString( "http://www.google.com" );
Thanks
NSURLConnection is the class to use in Cocoa, it's usage is pretty straightforward...
Firstly you need to create an instance of NSURLRequest that encompasses the URL you wish to read...
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.stackoverflow.com"]
Create a NSURLConnection to handle your request...
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
Note the second parameter of the init method is a delegate. This delegate needs to implement the following set of methods...
connection:didReceiveResponse:
connection:didReceiveData:
connection:didFailWithError:
connectionDidFinishLoading:
Upon init of the NSURLConnection the download will commence. You can cancel it at any point by send the object a cancel message.
Once you have data to be read the connection will call the connection:didReceiveData: method on it's delegate passing an instance of NSData as the second parameter. This method will be called multiple times as your connection streams you data so use an instance of NSMutableData to aggregate the response...
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[mutableData appendData data];
}
Once the full contents of the URL have been read the connectionDidFinishLoading:(NSURLConnection*) method is invoked. At this point release the connection and use your data.
Check out the documentation for NSURLConnection. This is the asynchronous way to get at it. If you don't mind blocking the thread you can also check out stringWithContentsOfURL:encoding:error: on NSString.
Answer here:
objective c pulling content from website
Just remember to add the framework Webkit