user4992124 user4992124 - 1 month ago 20
iOS Question

MSMessage url stays nil after setting it to url of a file

I have an app with an iOS 10 iMessage app. When I attach my file URL to an

MSMessage
message.URL
is
(null)
. I really don't know what's causing this. When I check the logs, I see a proper url:
URL: file:///thisuser/...
etc. However,
message.URL
logs
(null)
.

I've build an
Exporter
class, this saves the file to disk and then returns the path for it.

+ (NSString *) saveToDisk:(NSDictionary *)dictionary {
// Figure out destination name (in public docs dir)
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *zippedName = [self getExportFileName:dictionary withExtension:YES];
NSString *zippedPath = [documentsDirectory stringByAppendingPathComponent:zippedName];

// Export to data buffer
NSData *gzData = [NSKeyedArchiver archivedDataWithRootObject:dictionary];

if (gzData == nil) return FALSE;

// Write to disk
[gzData writeToFile:zippedPath atomically:YES];

return zippedPath;
}


This will return something like:
/Users/thisuses/Library/Developer/CoreSimulator/Devices/.../Documents/new-save.rst
, where
.rst
is a custom file extension just for my app. This, in turn, is added to the
MSMessage
.

MSConversation *conversation = [self activeConversation];

MSMessageTemplateLayout *layout = [[MSMessageTemplateLayout alloc] init];
layout.image = [UIImage imageNamed:@"test"];
layout.caption = url.host;

MSMessage *message = [[MSMessage alloc] init];
message.layout = layout;

NSLog(@"Converter: %@", [Converter toDictionary:array]);
NSLog(@"Exporter: %@", [Exporter saveToDisk:[Converter toDictionary:array]]);
NSLog(@"URL: %@", [NSURL fileURLWithPath:[Exporter saveToDisk:[Converter toDictionary:array]]]);

message.URL = [NSURL fileURLWithPath:[Exporter saveToDisk:[Converter toDictionary:array]]];

NSLog(@"Message URL 1: %@", message.URL);

[conversation insertMessage:message completionHandler:^(NSError * error) {
NSLog(@"MSConvo error: %@",error);
}];


==
Edit: I added a check to the code to see if the Exporter returns a valid file path and turns out, it does.

NSURL *fileURL = [NSURL fileURLWithPath:[Exporter saveRequestToDisk:[Converter databaseToRequest:history]]];

if ([fileURL isFileURL]) {
NSLog(@"is File URL!");
message.URL = fileURL;
}

Answer

After looking into the docs and skimming this article, I think that the url property is not supposed to point to a file. Instead it should

[...][encode] data to be transmitted with the message.

I guess the right way to go is to

Encode your application’s data in the URL. For example, you can encode data as key-value pairs in the URL’s query string, as shown below:

guard let components = NSURLComponents(string: myBaseURL) else {
    fatalError("Invalid base url")
}

let size = NSURLQueryItem(name: "Size", value: "Large")
let count = NSURLQueryItem(name: "Topping_Count", value: "2")
let cheese = NSURLQueryItem(name: "Topping_0", value: "Cheese")
let pepperoni = NSURLQueryItem(name: "Topping_1", value: "Pepperoni")
components.queryItems = [size, count, cheese, pepperoni]

guard let url = components.url  else {
    fatalError("Invalid URL components.")
}

message.url = url

(Code taken from the docs, you might want to convert it to ObjC...)

So instead of converting your dictionary to NSData and writing it to a file, you might want to encode it into queryItems, possibly like this:

NSMutableArray *queryItems = [[NSMutableArray alloc] init]; // Or initWithCapacity for the sake of performance...
NSDictionary *dict = [Converter toDictionary:array];

for (id key in dict) {
    id value = queryDictionary[key];
    NSURLQueryItem *queryItem = [NSURLQueryItem queryItemWithName:key value:value];
    [queryItems addObject:queryItem];
}

[url setQueryItems:queryItems];
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