Use content proxy to configure all proxied content requests.

Signal/src/network/GiphyAPI.swift

@@ -310,6 +310,12 @@ extension GiphyError: LocalizedError {
         }
         let urlString = "/v1/gifs/search?api_key=\(kGiphyApiKey)&offset=\(kGiphyPageOffset)&limit=\(kGiphyPageSize)&q=\(queryEncoded)"
 
+        guard ContentProxy.configureSessionManager(sessionManager: sessionManager, forUrl: urlString) else {
+            owsFailDebug("Could not configure query: \(query).")
+            failure(nil)
+            return
+        }
+
         sessionManager.get(urlString,
                            parameters: [String: AnyObject](),
                            progress: nil,

SignalServiceKit/src/Messages/Interactions/OWSLinkPreview.swift

@@ -589,10 +589,10 @@ public class OWSLinkPreview: MTLModel {
         }
     }
 
-    class func downloadLink(url: String,
+    class func downloadLink(url urlString: String,
                             remainingRetries: UInt = 3) -> Promise<Data> {
 
-        Logger.verbose("url: \(url)")
+        Logger.verbose("url: \(urlString)")
 
         let sessionConfiguration = ContentProxy.sessionConfiguration()
 
@@ -605,13 +605,13 @@ public class OWSLinkPreview: MTLModel {
         sessionManager.requestSerializer = AFHTTPRequestSerializer()
         sessionManager.responseSerializer = AFHTTPResponseSerializer()
 
-        // Remove all headers from the request.
-        for headerField in sessionManager.requestSerializer.httpRequestHeaders.keys {
-            sessionManager.requestSerializer.setValue(nil, forHTTPHeaderField: headerField)
+        guard ContentProxy.configureSessionManager(sessionManager: sessionManager, forUrl: urlString) else {
+            owsFailDebug("Could not configure url: \(urlString).")
+            return Promise(error: LinkPreviewError.assertionFailure)
         }
 
         let (promise, resolver) = Promise<Data>.pending()
-        sessionManager.get(url,
+        sessionManager.get(urlString,
                            parameters: [String: AnyObject](),
                            progress: nil,
                            success: { task, value in
@@ -654,7 +654,7 @@ public class OWSLinkPreview: MTLModel {
                                 resolver.reject(LinkPreviewError.couldNotDownload)
                                 return
                             }
-                            OWSLinkPreview.downloadLink(url: url, remainingRetries: remainingRetries - 1)
+                            OWSLinkPreview.downloadLink(url: urlString, remainingRetries: remainingRetries - 1)
                             .done(on: DispatchQueue.global()) { (data) in
                                 resolver.fulfill(data)
                             }.catch(on: DispatchQueue.global()) { (error) in

SignalServiceKit/src/Network/ContentProxy.swift

@@ -51,4 +51,102 @@ public class ContentProxy: NSObject {
         sessionManager.responseSerializer = AFJSONResponseSerializer()
         return sessionManager
     }
-}
+
+    static let userAgent = "Signal iOS (+https://signal.org/download)"
+
+    public class func configureProxiedRequest(request: inout URLRequest) -> Bool {
+        request.addValue(userAgent, forHTTPHeaderField: "User-Agent")
+
+        padRequestSize(request: &request)
+
+        guard let url = request.url,
+        let scheme = url.scheme,
+            scheme.lowercased() == "https" else {
+                return false
+        }
+        return true
+    }
+
+    @objc
+    public class func configureSessionManager(sessionManager: AFHTTPSessionManager,
+                                              forUrl urlString: String) -> Bool {
+
+        guard let url = URL(string: urlString, relativeTo: sessionManager.baseURL) else {
+            owsFailDebug("Invalid URL query: \(urlString).")
+            return false
+        }
+
+        var request = URLRequest(url: url)
+
+        guard configureProxiedRequest(request: &request) else {
+            owsFailDebug("Invalid URL query: \(urlString).")
+            return false
+        }
+
+        // Remove all headers from the request.
+        for headerField in sessionManager.requestSerializer.httpRequestHeaders.keys {
+            sessionManager.requestSerializer.setValue(nil, forHTTPHeaderField: headerField)
+        }
+        // Honor the request's headers.
+        if let allHTTPHeaderFields = request.allHTTPHeaderFields {
+            for (headerField, headerValue) in allHTTPHeaderFields {
+                sessionManager.requestSerializer.setValue(headerValue, forHTTPHeaderField: headerField)
+            }
+        }
+        return true
+    }
+
+    public class func padRequestSize(request: inout URLRequest) {
+        guard let sizeEstimate: UInt = estimateRequestSize(request: request) else {
+            owsFailDebug("Could not estimate request size.")
+            return
+        }
+        // We pad the estimated size to an even multiple of paddingQuantum (plus the
+        // extra ": " and "\r\n").  The exact size doesn't matter so long as the
+        // padding is consistent.
+        let paddingQuantum: UInt = 1024
+        let paddingSize = paddingQuantum - (sizeEstimate % paddingQuantum)
+        let padding = String(repeating: ".", count: Int(paddingSize))
+        request.addValue(padding, forHTTPHeaderField: "X-SignalPadding")
+    }
+
+    private class func estimateRequestSize(request: URLRequest) -> UInt? {
+        // iOS doesn't offer an exact way to measure request sizes on the wire,
+        // but we can reliably estimate request sizes using the "knowns", e.g.
+        // HTTP method, path, querystring, headers.  The "unknowns" should be
+        // consistent between requests.
+
+        guard let url = request.url?.absoluteString else {
+            owsFailDebug("Request missing URL.")
+            return nil
+        }
+        guard let components = URLComponents(string: url) else {
+            owsFailDebug("Request has invalid URL.")
+            return nil
+        }
+
+        var result: Int = 0
+
+        if let httpMethod = request.httpMethod {
+            result += httpMethod.count
+        }
+        result += components.percentEncodedPath.count
+        if let percentEncodedQuery = components.percentEncodedQuery {
+            result += percentEncodedQuery.count
+        }
+        if let allHTTPHeaderFields = request.allHTTPHeaderFields {
+            for (key, value) in allHTTPHeaderFields {
+                // Each header has 4 extra bytes:
+                //
+                // * Two for the key/value separator ": "
+                // * Two for "\r\n", the line break in the HTTP protocol spec.
+                result += key.count + value.count + 4
+            }
+        } else {
+            owsFailDebug("Request has no headers.")
+        }
+        if let httpBody = request.httpBody {
+            result += httpBody.count
+        }
+        return UInt(result)
+    }}

SignalServiceKit/src/Network/ProxiedContentDownloader.swift

@@ -657,8 +657,6 @@ open class ProxiedContentDownloader: NSObject, URLSessionTaskDelegate, URLSessio
             return
         }
 
-        let userAgent = "Signal iOS (+https://signal.org/download)"
-
         if assetRequest.state == .waiting {
             // If asset request hasn't yet determined the resource size,
             // try to do so now, by requesting a small initial segment.
@@ -671,8 +669,14 @@ open class ProxiedContentDownloader: NSObject, URLSessionTaskDelegate, URLSessio
             request.httpShouldUsePipelining = true
             let rangeHeaderValue = "bytes=\(segmentStart)-\(segmentStart + segmentLength - 1)"
             request.addValue(rangeHeaderValue, forHTTPHeaderField: "Range")
-            request.addValue(userAgent, forHTTPHeaderField: "User-Agent")
-            padRequestSize(request: &request)
+
+            guard ContentProxy.configureProxiedRequest(request: &request) else {
+                assetRequest.state = .failed
+                assetRequestDidFail(assetRequest: assetRequest)
+                processRequestQueueSync()
+                return
+            }
+
             let task = downloadSession.dataTask(with: request, completionHandler: { data, response, error -> Void in
                 self.handleAssetSizeResponse(assetRequest: assetRequest, data: data, response: response, error: error)
             })
@@ -692,8 +696,14 @@ open class ProxiedContentDownloader: NSObject, URLSessionTaskDelegate, URLSessio
             request.httpShouldUsePipelining = true
             let rangeHeaderValue = "bytes=\(assetSegment.segmentStart)-\(assetSegment.segmentStart + assetSegment.segmentLength - 1)"
             request.addValue(rangeHeaderValue, forHTTPHeaderField: "Range")
-            request.addValue(userAgent, forHTTPHeaderField: "User-Agent")
-            padRequestSize(request: &request)
+
+            guard ContentProxy.configureProxiedRequest(request: &request) else {
+                assetRequest.state = .failed
+                assetRequestDidFail(assetRequest: assetRequest)
+                processRequestQueueSync()
+                return
+            }
+
             let task: URLSessionDataTask = downloadSession.dataTask(with: request)
             task.assetRequest = assetRequest
             task.assetSegment = assetSegment
@@ -705,64 +715,6 @@ open class ProxiedContentDownloader: NSObject, URLSessionTaskDelegate, URLSessio
         processRequestQueueSync()
     }
 
-    private func padRequestSize(request: inout URLRequest) {
-        guard let sizeEstimate: UInt = estimateRequestSize(request: request) else {
-            owsFailDebug("Could not estimate request size.")
-            return
-        }
-        // We pad the estimated size to an even multiple of paddingQuantum (plus the
-        // extra ": " and "\r\n").  The exact size doesn't matter so long as the
-        // padding is consistent.
-        let paddingQuantum: UInt = 1024
-        let paddingSize = paddingQuantum - (sizeEstimate % paddingQuantum)
-        let padding = String(repeating: ".", count: Int(paddingSize))
-        request.addValue(padding, forHTTPHeaderField: "X-SignalPadding")
-    }
-
-    private func estimateRequestSize(request: URLRequest) -> UInt? {
-        // iOS doesn't offer an exact way to measure request sizes on the wire,
-        // but we can reliably estimate request sizes using the "knowns", e.g.
-        // HTTP method, path, querystring, headers.  The "unknowns" should be
-        // consistent between requests.
-
-        guard let url = request.url?.absoluteString else {
-            owsFailDebug("Request missing URL.")
-            return nil
-        }
-        guard let components = URLComponents(string: url) else {
-            owsFailDebug("Request has invalid URL.")
-            return nil
-        }
-
-        var result: Int = 0
-
-        if let httpMethod = request.httpMethod {
-            result += httpMethod.count
-        }
-        result += components.percentEncodedPath.count
-        if let percentEncodedQuery = components.percentEncodedQuery {
-            result += percentEncodedQuery.count
-        }
-        if let allHTTPHeaderFields = request.allHTTPHeaderFields {
-            if allHTTPHeaderFields.count != 2 {
-                owsFailDebug("Request has unexpected number of headers.")
-            }
-            for (key, value) in allHTTPHeaderFields {
-                // Each header has 4 extra bytes:
-                //
-                // * Two for the key/value separator ": "
-                // * Two for "\r\n", the line break in the HTTP protocol spec.
-                result += key.count + value.count + 4
-            }
-        } else {
-            owsFailDebug("Request has no headers.")
-        }
-        if let httpBody = request.httpBody {
-            result += httpBody.count
-        }
-        return UInt(result)
-    }
-
     private func handleAssetSizeResponse(assetRequest: ProxiedContentAssetRequest, data: Data?, response: URLResponse?, error: Error?) {
         guard error == nil else {
             assetRequest.state = .failed