I have to check series of operations sequentially. but in case of any operation failed i need to call other operation before executing listed operation in queue.
for example:
priority 1 : Fetch all companies lookups
priority 2 : Fetch all regions
priority 3...N : Fetch all cities individually for each region
in each operation i pass one key which valid only for 2 hours... suppose key was generated on 10am and i will start fetching data from server and it will take 15 mins to fetch all data completely.
but the problem is i have started fetching data on 11:59 am and during fetching information key expired. so i need to send one more request to get key and proceed further for next operations.
so it looks like:
priority 1 : Fetch all companies lookups with key
priority 2 : Fetch all regions (i.e. 4 Regions available) with key
priority 3 : Fetch all cities for region 1 with key
priority 4 : Fetch all cities for region 2 with key (here key is expire) so for taking new key need to add new operation here, which fetch new key which is valid again for next two hours.
priority 5 : Fetch all cities for region 3 with new key
priority 6 : Fetch all cities for region 4 with new key
Code which i have tried:
var queue = NSOperationQueue.mainQueue()
queue.addOperationWithBlock({
callService(“http://dsn/FetchingCompanyData”)
}
queue.addOperationWithBlock({
callService(“http://dsn/FetchingRegionData”)
//get region List here
for region in regions{
queue.addOperationWithBlock({
callService(“http://dsn/FetchingCities?region=\(region.code)”)
//check in response if response return message like KEY_EXPIRE
if(error){
queue.addOperationWithBlock({
var newKey = callService(“http://dsn/FetchingCities?region=\(region.code)”)
setKeyToCache(newKey)
})
}
}
}
}
fun callService(urlStr: String){
let myURL = NSURL(string: urlStr)!
var key = getKeyFromCache()
var request = NSMutableURLRequest(URL: myURL)
var errorHandling = ErrorHandling()
request.HTTPMethod = "POST"
request.timeoutInterval = 10000.0
request.addValue("application/xml", forHTTPHeaderField: "Content-Type")
request.addValue("application/xml", forHTTPHeaderField: "Accept")
request.setValue("Basic \(key)", forHTTPHeaderField: "Authorization")
NSURLConnection.sendAsynchronousRequest(request, queue: queue) { response, data, error in ..}
}
this code is not working as desire.
it adding operations in queue as below:
Queue:
Operation 1: Fetch companies
Operation 2: Fetch Regions
Operation 3: Fetch cities for region 1
Operation 4: Fetch cities for region 2
Operation 5: Fetch cities for region 3
Operation 6: Fetch cities for region 4
Operation 7: Fetch new key for region 1
Operation 7: Fetch new key for region 2
Operation 7: Fetch new key for region 3
Operation 7: Fetch new key for region 4
instead of this i want sequence of operations as below.
Operation 1: Fetch companies
Operation 2: Fetch Regions
Operation 3: Fetch cities for region 1
Operation 4: Fetch cities for region 2
Operation 5: Fetch new key for region 2
Operation 6: Again Fetch cities for region 2
Operation 7: Fetch cities for region 3
Operation 8: Fetch cities for region 4
Any help will be more appreciated.
resolved this issue by adding synchronous call instead of asynchronous.