Added a retry function

tise · Jan 17, 2018 · 6b53727 · 6b53727
1 parent a00256b
commit 6b53727
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diff --git a/Malibu.xcodeproj/project.pbxproj b/Malibu.xcodeproj/project.pbxproj
@@ -7,6 +7,9 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		08A262F2200F57940090E4CC /* Attempt.swift in Sources */ = {isa = PBXBuildFile; fileRef = 08A262F1200F57940090E4CC /* Attempt.swift */; };
+		08A262F3200F57940090E4CC /* Attempt.swift in Sources */ = {isa = PBXBuildFile; fileRef = 08A262F1200F57940090E4CC /* Attempt.swift */; };
+		08A262F4200F57940090E4CC /* Attempt.swift in Sources */ = {isa = PBXBuildFile; fileRef = 08A262F1200F57940090E4CC /* Attempt.swift */; };
 		D503D38D1C8DA7730009BDAD /* Serializing.swift in Sources */ = {isa = PBXBuildFile; fileRef = D503D38C1C8DA7730009BDAD /* Serializing.swift */; };
 		D503D38E1C8DA7730009BDAD /* Serializing.swift in Sources */ = {isa = PBXBuildFile; fileRef = D503D38C1C8DA7730009BDAD /* Serializing.swift */; };
 		D503D3901C8DA95B0009BDAD /* JsonSerializer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D503D38F1C8DA95B0009BDAD /* JsonSerializer.swift */; };
@@ -253,6 +256,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		08A262F1200F57940090E4CC /* Attempt.swift */ = {isa = PBXFileReference; indentWidth = 2; lastKnownFileType = sourcecode.swift; path = Attempt.swift; sourceTree = "<group>"; };
 		D500FD111C3AABED00782D78 /* Playground-iOS.playground */ = {isa = PBXFileReference; lastKnownFileType = file.playground; path = "Playground-iOS.playground"; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.swift; };
 		D503D38C1C8DA7730009BDAD /* Serializing.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Serializing.swift; sourceTree = "<group>"; };
 		D503D38F1C8DA95B0009BDAD /* JsonSerializer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = JsonSerializer.swift; sourceTree = "<group>"; };
@@ -503,6 +507,7 @@
 				D5339AF51D9C6C5900E8A7AD /* RequestStorage.swift */,
 				D5E8EDC21D9D865B0087690A /* RequestCapsule.swift */,
 				D5445A091E3CE16F00445406 /* RequestConvertible.swift */,
+				08A262F1200F57940090E4CC /* Attempt.swift */,
 			);
 			path = Request;
 			sourceTree = "<group>";
@@ -1104,6 +1109,7 @@
 				D51FC8611F73016300D722AD /* ParameterEncoding.swift in Sources */,
 				D51FC8681F73016300D722AD /* MultipartBuilder.swift in Sources */,
 				D51FC8761F73016300D722AD /* MimeType.swift in Sources */,
+				08A262F4200F57940090E4CC /* Attempt.swift in Sources */,
 				D51FC86C1F73016300D722AD /* ContentType.swift in Sources */,
 				D51FC87F1F73016300D722AD /* StringSerializer.swift in Sources */,
 				D51FC8811F73016300D722AD /* StatusCodeValidator.swift in Sources */,
@@ -1188,6 +1194,7 @@
 				D5B965201C922BDC0099D2F9 /* ResponseValidation.swift in Sources */,
 				DAC92A091C7F961900F01940 /* FormURLEncoder.swift in Sources */,
 				DAC92A061C7F90B400F01940 /* Malibu.swift in Sources */,
+				08A262F2200F57940090E4CC /* Attempt.swift in Sources */,
 				D5F357CF1D58BDE500153C41 /* MultipartBuilder.swift in Sources */,
 				DA5B4D0A1C8E59A2004E21ED /* Networking.swift in Sources */,
 				DAC92A391C87B95100F01940 /* StatusCodeValidator.swift in Sources */,
@@ -1272,6 +1279,7 @@
 				D5B965211C922BDC0099D2F9 /* ResponseValidation.swift in Sources */,
 				DAC92A0A1C7F961900F01940 /* FormURLEncoder.swift in Sources */,
 				DAC92A071C7F90B400F01940 /* Malibu.swift in Sources */,
+				08A262F3200F57940090E4CC /* Attempt.swift in Sources */,
 				D5F357D01D58BDE500153C41 /* MultipartBuilder.swift in Sources */,
 				DA5B4D0B1C8E59A2004E21ED /* Networking.swift in Sources */,
 				DAC92A3A1C87B95100F01940 /* StatusCodeValidator.swift in Sources */,

diff --git a/Sources/NetworkError.swift b/Sources/NetworkError.swift
@@ -11,6 +11,7 @@ public enum NetworkError: Error {
   case jsonArraySerializationFailed(response: Response)
   case jsonDictionarySerializationFailed(response: Response)
   case stringSerializationFailed(encoding: UInt, response: Response)
+  case tooManyFailedAttempts(attempts: Int, errors: [Error])
 
   public var reason: String {
     var text: String
@@ -36,6 +37,8 @@ public enum NetworkError: Error {
       text = "No JSON dictionary in response data"
     case .stringSerializationFailed(let encoding, _):
       text = "String could not be serialized with encoding: \(encoding)"
+    case .tooManyFailedAttempts(let attemptCount, _):
+        text = "Request exceeded maximum number of failures (\(attemptCount))"
     }
 
     return NSLocalizedString(text, comment: "")

diff --git a/Sources/Request/Attempt.swift b/Sources/Request/Attempt.swift
@@ -0,0 +1,36 @@
+import Foundation
+import When
+
+func attempt(_ request: @escaping () -> NetworkPromise) -> NetworkPromise {
+  return attempt(request: request)
+}
+
+func attempt(request: @escaping () -> NetworkPromise,
+             maximumAttempts: Int = 5,
+             retryInterval: TimeInterval = 0.2,
+             queue: DispatchQueue = .main) -> NetworkPromise
+{
+  let promise = NetworkPromise()
+
+  var attempts = 0
+  var errors = [Error]()
+
+  func attempt() {
+    request()
+      .done { response in
+        promise.resolve(response)
+      }
+      .fail { error in
+        if attempts < maximumAttempts {
+          attempts += 1
+          errors.append(error)
+          queue.asyncAfter(deadline: .now() + retryInterval, execute: attempt)
+        } else {
+          promise.reject(NetworkError.tooManyFailedAttempts(attempts: attempts, errors: errors))
+        }}
+  }
+
+  attempt()
+
+  return promise
+}