diff --git a/ext/native/base/buffer.cpp b/ext/native/base/buffer.cpp
index 68cc412dd3e0..2c28a09f7b0f 100644
--- a/ext/native/base/buffer.cpp
+++ b/ext/native/base/buffer.cpp
@@ -152,11 +152,22 @@ bool Buffer::FlushToFile(const char *filename) {
 	return true;
 }
 
-bool Buffer::FlushSocket(uintptr_t sock, double timeout) {
+bool Buffer::FlushSocket(uintptr_t sock, double timeout, bool *cancelled) {
+	static constexpr float CANCEL_INTERVAL = 0.25f;
 	for (size_t pos = 0, end = data_.size(); pos < end; ) {
-		if (timeout >= 0.0 && !fd_util::WaitUntilReady(sock, timeout, true)) {
-			ELOG("FlushSocket timed out");
-			return false;
+		bool ready = false;
+		double leftTimeout = timeout;
+		while (!ready && (leftTimeout >= 0 || cancelled)) {
+			if (cancelled && *cancelled)
+				return false;
+			ready = fd_util::WaitUntilReady(sock, CANCEL_INTERVAL, true);
+			if (!ready && leftTimeout >= 0.0) {
+				leftTimeout -= CANCEL_INTERVAL;
+				if (leftTimeout < 0) {
+					ELOG("FlushSocket timed out");
+					return false;
+				}
+			}
 		}
 		int sent = send(sock, &data_[pos], (int)(end - pos), MSG_NOSIGNAL);
 		if (sent < 0) {
@@ -199,6 +210,7 @@ bool Buffer::ReadAll(int fd, int hintSize) {
 }
 
 bool Buffer::ReadAllWithProgress(int fd, int knownSize, float *progress, bool *cancelled) {
+	static constexpr float CANCEL_INTERVAL = 0.25f;
 	std::vector<char> buf;
 	if (knownSize >= 65536 * 16) {
 		buf.resize(65536);
@@ -210,8 +222,12 @@ bool Buffer::ReadAllWithProgress(int fd, int knownSize, float *progress, bool *c
 
 	int total = 0;
 	while (true) {
-		if (cancelled && *cancelled)
-			return false;
+		bool ready = false;
+		while (!ready && cancelled) {
+			if (*cancelled)
+				return false;
+			ready = fd_util::WaitUntilReady(fd, CANCEL_INTERVAL, false);
+		}
 		int retval = recv(fd, &buf[0], (int)buf.size(), 0);
 		if (retval == 0) {
 			return true;
@@ -222,7 +238,8 @@ bool Buffer::ReadAllWithProgress(int fd, int knownSize, float *progress, bool *c
 		char *p = Append((size_t)retval);
 		memcpy(p, &buf[0], retval);
 		total += retval;
-		*progress = (float)total / (float)knownSize;
+		if (progress)
+			*progress = (float)total / (float)knownSize;
 	}
 	return true;
 }
diff --git a/ext/native/base/buffer.h b/ext/native/base/buffer.h
index b34901fb1716..87018a399981 100644
--- a/ext/native/base/buffer.h
+++ b/ext/native/base/buffer.h
@@ -64,7 +64,7 @@ class Buffer {
 	// written.
 	bool Flush(int fd);
 	bool FlushToFile(const char *filename);
-	bool FlushSocket(uintptr_t sock, double timeout = -1.0);  // Windows portability
+	bool FlushSocket(uintptr_t sock, double timeout = -1.0, bool *cancelled = nullptr);  // Windows portability
 
   bool ReadAll(int fd, int hintSize = 0);
   bool ReadAllWithProgress(int fd, int knownSize, float *progress, bool *cancelled);
diff --git a/ext/native/net/http_client.cpp b/ext/native/net/http_client.cpp
index ca2fb0f36c1e..29641aff7754 100644
--- a/ext/native/net/http_client.cpp
+++ b/ext/native/net/http_client.cpp
@@ -229,13 +229,13 @@ int Client::GET(const char *resource, Buffer *output, std::vector<std::string> &
 	const char *otherHeaders =
 		"Accept: */*\r\n"
 		"Accept-Encoding: gzip\r\n";
-	int err = SendRequest("GET", resource, otherHeaders, progress);
+	int err = SendRequest("GET", resource, otherHeaders, progress, cancelled);
 	if (err < 0) {
 		return err;
 	}
 
 	Buffer readbuf;
-	int code = ReadResponseHeaders(&readbuf, responseHeaders, progress);
+	int code = ReadResponseHeaders(&readbuf, responseHeaders, progress, cancelled);
 	if (code < 0) {
 		return code;
 	}
@@ -283,11 +283,11 @@ int Client::POST(const char *resource, const std::string &data, Buffer *output,
 	return POST(resource, data, "", output, progress);
 }
 
-int Client::SendRequest(const char *method, const char *resource, const char *otherHeaders, float *progress) {
-	return SendRequestWithData(method, resource, "", otherHeaders, progress);
+int Client::SendRequest(const char *method, const char *resource, const char *otherHeaders, float *progress, bool *cancelled) {
+	return SendRequestWithData(method, resource, "", otherHeaders, progress, cancelled);
 }
 
-int Client::SendRequestWithData(const char *method, const char *resource, const std::string &data, const char *otherHeaders, float *progress) {
+int Client::SendRequestWithData(const char *method, const char *resource, const std::string &data, const char *otherHeaders, float *progress, bool *cancelled) {
 	if (progress) {
 		*progress = 0.01f;
 	}
@@ -314,12 +314,24 @@ int Client::SendRequestWithData(const char *method, const char *resource, const
 	return 0;
 }
 
-int Client::ReadResponseHeaders(Buffer *readbuf, std::vector<std::string> &responseHeaders, float *progress) {
+int Client::ReadResponseHeaders(Buffer *readbuf, std::vector<std::string> &responseHeaders, float *progress, bool *cancelled) {
 	// Snarf all the data we can into RAM. A little unsafe but hey.
-	if (dataTimeout_ >= 0.0 && !fd_util::WaitUntilReady(sock(), dataTimeout_, false)) {
-		ELOG("HTTP headers timed out");
-		return -1;
-	}
+	static constexpr float CANCEL_INTERVAL = 0.25f;
+	bool ready = false;
+	double leftTimeout = dataTimeout_;
+	while (!ready) {
+		if (cancelled && *cancelled)
+			return -1;
+		ready = fd_util::WaitUntilReady(sock(), CANCEL_INTERVAL, false);
+		if (!ready && leftTimeout >= 0.0) {
+			leftTimeout -= CANCEL_INTERVAL;
+			if (leftTimeout < 0) {
+				ELOG("HTTP headers timed out");
+				return -1;
+			}
+		}
+	};
+	// Let's hope all the headers are available in a single packet...
 	if (readbuf->Read(sock(), 4096) < 0) {
 		ELOG("Failed to read HTTP headers :(");
 		return -1;
@@ -396,7 +408,7 @@ int Client::ReadResponseEntity(Buffer *readbuf, const std::vector<std::string> &
 
 	if (!contentLength || !progress) {
 		// No way to know how far along we are. Let's just not update the progress counter.
-		if (!readbuf->ReadAll(sock(), contentLength))
+		if (!readbuf->ReadAllWithProgress(sock(), contentLength, nullptr, cancelled))
 			return -1;
 	} else {
 		// Let's read in chunks, updating progress between each.
diff --git a/ext/native/net/http_client.h b/ext/native/net/http_client.h
index 694cad33edfc..9c935858face 100644
--- a/ext/native/net/http_client.h
+++ b/ext/native/net/http_client.h
@@ -71,9 +71,9 @@ class Client : public net::Connection {
 
 	// HEAD, PUT, DELETE aren't implemented yet, but can be done with SendRequest.
 
-	int SendRequest(const char *method, const char *resource, const char *otherHeaders = nullptr, float *progress = nullptr);
-	int SendRequestWithData(const char *method, const char *resource, const std::string &data, const char *otherHeaders = nullptr, float *progress = nullptr);
-	int ReadResponseHeaders(Buffer *readbuf, std::vector<std::string> &responseHeaders, float *progress = nullptr);
+	int SendRequest(const char *method, const char *resource, const char *otherHeaders = nullptr, float *progress = nullptr, bool *cancelled = nullptr);
+	int SendRequestWithData(const char *method, const char *resource, const std::string &data, const char *otherHeaders = nullptr, float *progress = nullptr, bool *cancelled = nullptr);
+	int ReadResponseHeaders(Buffer *readbuf, std::vector<std::string> &responseHeaders, float *progress = nullptr, bool *cancelled = nullptr);
 	// If your response contains a response, you must read it.
 	int ReadResponseEntity(Buffer *readbuf, const std::vector<std::string> &responseHeaders, Buffer *output, float *progress = nullptr, bool *cancelled = nullptr);