http_reader: improve robustness of header reading

It's possible for networks and servers to break up
even small HTTP headers.  We also better enforce the
timeout if we too too long to write the request.

1 files changed, 6 insertions, 5 deletions

diff --git a/lib/mogilefs/http_reader.rb b/lib/mogilefs/http_reader.rb
index 3afaae0..8a0337e 100644
--- a/lib/mogilefs/http_reader.rb
+++ b/lib/mogilefs/http_reader.rb
@@ -50,17 +50,18 @@ class MogileFS::HTTPReader < MogileFS::Socket
   # body of the response.
   def self.try(path, timeout, range) # :nodoc:
     uri = URI.parse(path)
+    expire_at = Time.now + timeout
     sock = tcp(uri.host, uri.port, timeout)
     buf = "GET #{uri.request_uri} HTTP/1.0\r\n#{range}\r\n" # no chunking
     sock.timed_write(buf, timeout)
 
-    sock.timed_peek(2048, buf, timeout) or
-      raise MogileFS::InvalidResponseError, "EOF while reading header", []
+    begin
+      raise MogileFS::Timeout if Time.now > expire_at
+      sock.timed_peek(2048, buf, timeout) or
+        raise MogileFS::InvalidResponseError, "EOF while reading header", []
+    end until /\r\n\r\n/ =~ buf
 
     head, _ = buf.split(/\r\n\r\n/, 2)
-
-    # we're dealing with a seriously slow/stupid HTTP server if we can't
-    # get the header in a single recv(2) syscall.
     if ((range && head =~ %r{\AHTTP/\d+\.\d+\s+206\s*}) ||
         (!range && head =~ %r{\AHTTP/\d+\.\d+\s+200\s*})) &&
        head =~ %r{^Content-Length:\s*(\d+)}i