Combine Multiple Network Requests with ReactiveCocoa - afnetworking

Question

I'm exploring ReactiveCocoa and trying to see whats possible. The issues i'm having is chaining a few network requests together.
I have 2 calls, the first gets a list of identifiers, then for each identifier I make a call to get data corresponding to that id and create a model object and return an array of the objects.
I'm using RACExtensions for AFNetworking to make the requests. Code looks something like this:
- (RACSignal *) identifersInfo
{
return [[[[self identifiersSignal] flattenMap:^RACStream *(RACTuple *tuple) {
RACTupleUnpack(AFHTTPRequestOperation *operation, id responseObject) = tuple;
NSArray *identifiers = responseObject[#"Identifiers"];
NSArray *requests = [self httpRequestsWithIdentifiers: identifiers];
return [self.client rac_enqueueBatchOfHTTPRequestOperationsWithRequests: requests];
}] collect] map:^id(RACTuple *tuple) {
RACTupleUnpack(AFHTTPRequestOperation *operation, id responseObject) = tuple;
Model *model = [[Model alloc] init];
model.title = responseObject[#"Title"];
model.description = responseObject[#"Description"];
model.lastUpdated = responseObject[#"LastUpdated"];
return model;
}];
}
identifiersSignal method looks like this:
- (RACSignal *) identifiersSignal
{
return [self.client rac_getPath: #"identifiers" parameters: nil];
}
This returns json dictionary which looks like:
{
"Identifiers": [
3,
4,
21
]
}
I'm actually mocking these calls at the moment and I know they work independently, I'm just trying to piece them together using ReacticeCocoa.
I can't figure out or find any decent samples on how this could be achieved using ReactiveCocoa, although I'm pretty confident it could be.

Answer 1

I had to look into the implementation of the AFNetworking extensions but I think you are misusing a some return values. I haven't tested but it seems like your code should look like this:
- (RACSignal *) identifersInfo {
return [[[self identifiersSignal] map:^RACSignal *(RACTuple *tuple) {
RACTupleUnpack(AFHTTPRequestOperation *operation, id responseObject) = tuple;
NSArray *identifiers = responseObject[#"Identifiers"];
NSArray *requests = [self httpRequestsWithIdentifiers: identifiers];
return [self.client rac_enqueueBatchOfHTTPRequestOperationsWithRequests: requests];
}] map:^Model*(id *reponseObject) {
Model *model = [[Model alloc] init];
// same as above
return model;
}];
}
It is a little misleading that rac_getPath returns a RACTuple as rac_enqueueBatchOfHTTPRequestOperationsWithRequests returns only a RACStream of the return objects. AFURLConnectionOperation+RACSupport.m The documentation in the header files should be improved with type information to get this straightened out.
Nice code, though.