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RSC15a (#384)
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@ricardopereira @tcard
ricardopereira authored and tcard committed May 16, 2016
1 parent 46cf77f commit 2fc9c76
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Showing 5 changed files with 131 additions and 40 deletions.
7 changes: 7 additions & 0 deletions Source/ARTFallback.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,15 @@
//

#import <Foundation/Foundation.h>
#import "CompatibilityMacros.h"

ART_ASSUME_NONNULL_BEGIN

@class ARTHttpResponse;
@class ARTClientOptions;

extern int (^ARTFallback_getRandomHostIndex)(int count);

@interface ARTFallback : NSObject
{

Expand All @@ -22,3 +27,5 @@
-(NSString *) popFallbackHost;

@end

ART_ASSUME_NONNULL_END
6 changes: 5 additions & 1 deletion Source/ARTFallback.m
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,10 @@
#import "ARTHttp.h"
#import "ARTClientOptions.h"

int (^ARTFallback_getRandomHostIndex)(int count) = ^int(int count) {
return arc4random() % count;
};

@interface ARTFallback ()

@property (readwrite, strong, nonatomic) NSMutableArray * hosts;
Expand All @@ -28,7 +32,7 @@ - (id)init {
NSMutableArray * hostArray =[[NSMutableArray alloc] initWithArray: [ARTDefault fallbackHosts]];
size_t count = [hostArray count];
for(int i=0; i <count; i++ ) {
int randomIndex = arc4random() % [hostArray count];
int randomIndex = ARTFallback_getRandomHostIndex((int)[hostArray count]);
[self.hosts addObject:[hostArray objectAtIndex:randomIndex]];
[hostArray removeObjectAtIndex:randomIndex];
}
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10 changes: 5 additions & 5 deletions Source/ARTRest.m
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Original file line number Diff line number Diff line change
Expand Up @@ -122,10 +122,10 @@ - (void)executeRequestWithAuthentication:(NSMutableURLRequest *)request withMeth
}

- (void)executeRequest:(NSMutableURLRequest *)request completion:(void (^)(NSHTTPURLResponse *__art_nullable, NSData *__art_nullable, NSError *__art_nullable))callback {
return [self executeRequest:request completion:callback fallbacks:nil];
return [self executeRequest:request completion:callback fallbacks:nil retries:0];
}

- (void)executeRequest:(NSMutableURLRequest *)request completion:(void (^)(NSHTTPURLResponse *__art_nullable, NSData *__art_nullable, NSError *__art_nullable))callback fallbacks:(ARTFallback *)fallbacks {
- (void)executeRequest:(NSMutableURLRequest *)request completion:(void (^)(NSHTTPURLResponse *__art_nullable, NSData *__art_nullable, NSError *__art_nullable))callback fallbacks:(ARTFallback *)fallbacks retries:(NSUInteger)retries {
__block ARTFallback *blockFallbacks = fallbacks;

[self.logger debug:__FILE__ line:__LINE__ message:@"%p executing request %@", self, request];
Expand All @@ -145,7 +145,7 @@ - (void)executeRequest:(NSMutableURLRequest *)request completion:(void (^)(NSHTT
error = dataError;
}
}
if ([self shouldRetryWithFallback:request response:response error:error]) {
if (retries < _options.httpMaxRetryCount && [self shouldRetryWithFallback:request response:response error:error]) {
if (!blockFallbacks && [request.URL.host isEqualToString:[ARTDefault restHost]]) {
blockFallbacks = [[ARTFallback alloc] init];
}
Expand All @@ -157,7 +157,7 @@ - (void)executeRequest:(NSMutableURLRequest *)request completion:(void (^)(NSHTT
NSURL *url = request.URL;
NSString *urlStr = [NSString stringWithFormat:@"%@://%@:%@%@?%@", url.scheme, host, url.port, url.path, (url.query ? url.query : @"")];
newRequest.URL = [NSURL URLWithString:urlStr];
[self executeRequest:newRequest completion:callback fallbacks:fallbacks];
[self executeRequest:newRequest completion:callback fallbacks:blockFallbacks retries:retries + 1];
return;
}
}
Expand Down Expand Up @@ -273,4 +273,4 @@ - (BOOL)stats:(ARTStatsQuery *)query callback:(void (^)(__GENERIC(ARTPaginatedRe
return self.encoders[self.defaultEncoding];
}

@end
@end
100 changes: 83 additions & 17 deletions Spec/RestClient.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -468,11 +468,12 @@ class RestClient: QuickSpec {
let channel = client.channels.get("test")

var capturedURLs = [String]()
testHTTPExecutor.afterRequest = { request in
testHTTPExecutor.afterRequest = { request, callback in
capturedURLs.append(request.URL!.absoluteString)
if testHTTPExecutor.requests.count == 2 {
// Stop
testHTTPExecutor.http = nil
callback!(nil, nil, nil)
}
}

Expand All @@ -490,26 +491,15 @@ class RestClient: QuickSpec {
expect(NSRegularExpression.match(capturedURLs[1], pattern: "//[a-e].ably-realtime.com")).to(beTrue())
}

}

// RSC15
context("Host Fallback") {

// RSC15e
it("every new HTTP request is first attempted to the primary host rest.ably.io") {
let options = ARTClientOptions(key: "xxxx:xxxx")
options.httpMaxRetryCount = 1
let client = ARTRest(options: options)
client.httpExecutor = testHTTPExecutor
testHTTPExecutor.http = MockHTTP(network: .HostUnreachable)
let channel = client.channels.get("test")

testHTTPExecutor.afterRequest = { _ in
if testHTTPExecutor.requests.count == 2 {
// Stop
testHTTPExecutor.http = nil
}
}

waitUntil(timeout: testTimeout) { done in
channel.publish(nil, data: "nil") { _ in
done()
Expand All @@ -533,10 +523,85 @@ class RestClient: QuickSpec {
expect(NSRegularExpression.match(testHTTPExecutor.requests[2].URL!.absoluteString, pattern: "//rest.ably.io")).to(beTrue())
}

}
// RSC15a
context("retry hosts in random order") {
let expectedHostOrder = [4, 3, 0, 2, 1]

// RSC15
context("Host Fallback") {
let originalARTFallback_getRandomHostIndex = ARTFallback_getRandomHostIndex

beforeEach {
ARTFallback_getRandomHostIndex = {
let hostIndexes = [1, 1, 0, 0, 0]
var i = 0
return { count in
let hostIndex = hostIndexes[i]
i += 1
return Int32(hostIndex)
}
}()
}

afterEach {
ARTFallback_getRandomHostIndex = originalARTFallback_getRandomHostIndex
}

it("until httpMaxRetryCount has been reached") {
let options = ARTClientOptions(key: "xxxx:xxxx")
let client = ARTRest(options: options)
options.httpMaxRetryCount = 3
client.httpExecutor = testHTTPExecutor
testHTTPExecutor.http = MockHTTP(network: .HostUnreachable)
testHTTPExecutor.afterRequest = { _, _ in
if testHTTPExecutor.requests.count > Int(1 + options.httpMaxRetryCount) {
fail("Should not retry more than \(options.httpMaxRetryCount)")
testHTTPExecutor.http = nil
}
}
let channel = client.channels.get("test")


waitUntil(timeout: testTimeout) { done in
channel.publish(nil, data: "nil") { _ in
done()
}
}

expect(testHTTPExecutor.requests).to(haveCount(Int(1 + options.httpMaxRetryCount)))

let extractHostname = { (request: NSMutableURLRequest) in
NSRegularExpression.extract(request.URL!.absoluteString, pattern: "[a-e].ably-realtime.com")
}
let resultFallbackHosts = testHTTPExecutor.requests.flatMap(extractHostname)
let expectedFallbackHosts = Array(expectedHostOrder.map({ ARTDefault.fallbackHosts()[$0] as! String })[0..<Int(options.httpMaxRetryCount)])

expect(resultFallbackHosts).to(equal(expectedFallbackHosts))
}

it("until all fallback hosts have been tried") {
let options = ARTClientOptions(key: "xxxx:xxxx")
options.httpMaxRetryCount = 10
let client = ARTRest(options: options)
client.httpExecutor = testHTTPExecutor
testHTTPExecutor.http = MockHTTP(network: .HostUnreachable)
let channel = client.channels.get("test")

waitUntil(timeout: testTimeout) { done in
channel.publish(nil, data: "nil") { _ in
done()
}
}

expect(testHTTPExecutor.requests).to(haveCount(ARTDefault.fallbackHosts().count + 1))

let extractHostname = { (request: NSMutableURLRequest) in
NSRegularExpression.extract(request.URL!.absoluteString, pattern: "[a-e].ably-realtime.com")
}
let resultFallbackHosts = testHTTPExecutor.requests.flatMap(extractHostname)
let expectedFallbackHosts = expectedHostOrder.map { ARTDefault.fallbackHosts()[$0] as! String }

expect(resultFallbackHosts).to(equal(expectedFallbackHosts))
}
}

// RSC15d
context("should use an alternative host when") {
Expand All @@ -551,10 +616,11 @@ class RestClient: QuickSpec {
testHTTPExecutor.http = MockHTTP(network: caseTest)
let channel = client.channels.get("test")

testHTTPExecutor.afterRequest = { _ in
testHTTPExecutor.afterRequest = { _, callback in
if testHTTPExecutor.requests.count == 2 {
// Stop
testHTTPExecutor.http = nil
callback!(nil, nil, nil)
}
}

Expand Down
48 changes: 31 additions & 17 deletions Spec/TestUtilities.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -544,30 +544,31 @@ class TestProxyHTTPExecutor: NSObject, ARTHTTPExecutor {
var requests: [NSMutableURLRequest] = []
var responses: [NSHTTPURLResponse] = []

var beforeRequest: Optional<(NSMutableURLRequest)->()> = nil
var afterRequest: Optional<(NSMutableURLRequest)->()> = nil
var beforeRequest: Optional<(NSMutableURLRequest, ((NSHTTPURLResponse?, NSData?, NSError?) -> Void)?)->()> = nil
var afterRequest: Optional<(NSMutableURLRequest, ((NSHTTPURLResponse?, NSData?, NSError?) -> Void)?)->()> = nil
var beforeProcessingDataResponse: Optional<(NSData?)->(NSData)> = nil

func executeRequest(request: NSMutableURLRequest, completion callback: ((NSHTTPURLResponse?, NSData?, NSError?) -> Void)?) {
guard let http = self.http else {
return
}
self.requests.append(request)
if let performEvent = beforeRequest {
performEvent(request)
}
if let http = self.http {
http.executeRequest(request, completion: { response, data, error in
if let httpResponse = response {
self.responses.append(httpResponse)
}
if let performEvent = self.beforeProcessingDataResponse {
callback?(response, performEvent(data), error)
}
else {
callback?(response, data, error)
}
})
performEvent(request, callback)
}
http.executeRequest(request, completion: { response, data, error in
if let httpResponse = response {
self.responses.append(httpResponse)
}
if let performEvent = self.beforeProcessingDataResponse {
callback?(response, performEvent(data), error)
}
else {
callback?(response, data, error)
}
})
if let performEvent = afterRequest {
performEvent(request)
performEvent(request, callback)
}
}

Expand Down Expand Up @@ -739,6 +740,19 @@ extension NSRegularExpression {
return regex.rangeOfFirstMatchInString(value, options: [], range: range).location != NSNotFound
}

class func extract(value: String?, pattern: String) -> String? {
guard let value = value else {
return nil
}
let options = NSRegularExpressionOptions()
let regex = try! NSRegularExpression(pattern: pattern, options: options)
let range = NSMakeRange(0, value.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
let result = regex.firstMatchInString(value, options: [], range: range)
guard let textRange = result?.rangeAtIndex(0) else { return nil }
let convertedRange = value.startIndex.advancedBy(textRange.location)..<value.startIndex.advancedBy(textRange.location+textRange.length)
return value.substringWithRange(convertedRange)
}

}

extension String {
Expand Down

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