Passing Query String Parameters When Sharing a Link Through Facebook iOS SDK

Facebook’s iOS SDK provides an efficient way to share content on the social network. However, one common challenge developers face is sharing links with query string parameters while maintaining their integrity during the sharing process.

In this article, we’ll explore how to pass query string parameters when sharing a link through Facebook’s iOS SDK, focusing on the FBSDKShareKit framework and its associated classes.

Understanding Query String Parameters

A query string parameter is an attribute appended to a URL that provides additional information about the request. In the context of sharing links, these parameters are crucial in conveying data from one application to another.

URL Encoding

When working with URLs in iOS development, it’s essential to consider URL encoding. This process involves replacing special characters (such as &, =, and %) with their corresponding escape sequences (%3D for = and %26 for &). URL encoding ensures that URLs remain valid and functional across different platforms.

When you share a link using Facebook’s iOS SDK, the following process occurs:

The FBSDKShareDialog instance is created with the shared content.
The dialog displays a UI to select the desired sharing method (e.g., “Post” or “Message”).
Once the user selects the method and taps “Post,” Facebook’s servers receive the request.
Before displaying the content, Facebook’s servers process the request by decoding the URL components.

Decoding URL Components

To decode URL components, you can use Apple’s URLComponents class, which provides methods for parsing and manipulating URLs. In this context, we’ll focus on decoding query string parameters.

Decoding Query String Parameters

#import &lt;Foundation/Foundation.h&gt;

- (NSString *)stringByRemovingPercentEncoding {
    return [self stringByAddingPercentEncodingWithAllowedCharacters:
           nil];
}

- (NSDictionary *)dictionaryFromQueryString:(NSString *)queryString {
    NSURLComponents *components = [NSURLComponents new];
    components.query = queryString;
    NSDictionary *parameters = [components parameters];

    // Remove any special characters from the parameter keys
    for (NSString *key in parameters) {
        key = [key stringByRemovingPercentEncoding];
    }

    return parameters;
}

In the provided code snippet, we’ve added two methods to decode query string parameters:

stringByRemovingPercentEncoding: Removes URL encoding by replacing % characters with a single character.
dictionaryFromQueryString: Creates an NSDictionary from the decoded query string.

Passing Query String Parameters

Now that we have a way to decode query string parameters, let’s explore how to pass them when sharing a link using Facebook’s iOS SDK.

Passing Query String Parameters with FBSDKShareKit

To share a link with query string parameters using FBSDKShareKit, you can create an instance of FBSDKShareLinkContent and set its properties accordingly:

#import &lt;FBSDKShareKit/FBSDKShareKit.h&gt;

- (void)shareWithQueryParams:(NSDictionary *)queryParams {
    FBSDKShareLinkContent *content = [[FBSDKShareLinkContent alloc] init];
    content.contentURL = [NSURL URLWithString:@"http://www.foo.com/message.html?s=This%20is%20a%20test%20&amp;%20an%20example"];
    content.contentDescription = @"Text for facebook";
    content.contentTitle = @"Results.";

    // Set query parameters
    if (queryParams) {
        FBSDKShareLinkContent *tempContent = [[FBSDKShareLinkContent alloc] init];
        tempContent.contentURL = [NSURL URLWithString:@"http://www.foo.com/message.html?s=This%20is%20a%20test%20&amp;%20an%20example"];
        for (NSString *key in queryParams) {
            NSString *value = queryParams[key];
            tempContent.contentURL.query = [NSString stringWithFormat:@"s=%@&amp;%@", value, tempContent.contentURL.query];
        }
        content = tempContent;
    }

    [FBSDKShareDialog showFromViewController:self
                                    withContent:content
                                       delegate:self];
}

In the provided code snippet, we’ve added a new method called shareWithQueryParams that allows you to pass query string parameters when sharing a link.

Conclusion

Sharing links with query string parameters can be challenging, especially when using Facebook’s iOS SDK. However, by understanding URL encoding and decoding techniques, as well as how to utilize FBSDKShareKit, developers can overcome these challenges and ensure their applications share data correctly.

By following the steps outlined in this article, you’ll be able to pass query string parameters when sharing a link through Facebook’s iOS SDK, resulting in more accurate data exchange between your application and other services.

Last modified on 2023-05-30