#4 Handles error objects send by fastcgi plugin in a special way to p…

…revent premature end of operation followed by a blank page for the user. Added also a integration test to ensure this.

.gitignore

@@ -1,5 +1,6 @@
 *.iml
-.idea
-.gradle
-build
-vendor
+/.idea
+/.gradle
+/build
+/vendor
+/learning

filter.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 	"strconv"
+	"github.com/mholt/caddy/caddyhttp/fastcgi"
 )
 
 const defaultMaxBufferSize = 10 * 1024 * 1024
@@ -27,11 +28,19 @@ func (instance filterHandler) ServeHTTP(writer http.ResponseWriter, request *htt
 	})
 	wrapper.maximumBufferSize = instance.maximumBufferSize
 	result, err := instance.next.ServeHTTP(wrapper, request)
+	var logError error
 	if err != nil {
-		return result, err
+		var ok bool
+		// This handles https://github.com/echocat/caddy-filter/issues/4
+		// If the fastcgi module is used and the FastCGI server produces log output
+		// this is send (by the FastCGI module) as an error. We have to check this and
+		// handle this case of error in a special way.
+		if logError, ok = err.(fastcgi.LogError); !ok {
+			return result, err
+		}
 	}
 	if !wrapper.wasSomethingRecorded() || !wrapper.isBodyAllowed() {
-		return result, nil
+		return result, logError
 	}
 	body := wrapper.recorded()
 	atLeastOneRuleMatched := false
@@ -55,5 +64,5 @@ func (instance filterHandler) ServeHTTP(writer http.ResponseWriter, request *htt
 	if n < len(body) {
 		return result, io.ErrShortWrite
 	}
-	return result, nil
+	return result, logError
 }

filter_test.go

@@ -6,6 +6,7 @@ import (
 	. "gopkg.in/check.v1"
 	"net/http"
 	"regexp"
+	"github.com/mholt/caddy/caddyhttp/fastcgi"
 )
 
 type filterTest struct {
@@ -68,6 +69,16 @@ func (s *filterTest) Test_withErrorInNext(c *C) {
 	c.Assert(s.writer.buffer.String(), Equals, "")
 }
 
+// This handles the bug https://github.com/echocat/caddy-filter/issues/4
+// See filter.go for more details.
+func (s *filterTest) Test_withLogErrorInNext(c *C) {
+	s.nextHandler.error = fastcgi.LogError("Oops")
+	status, err := s.handler.ServeHTTP(s.writer, s.request)
+	c.Assert(err, DeepEquals, s.nextHandler.error)
+	c.Assert(status, Equals, 200)
+	c.Assert(s.writer.buffer.String(), Equals, "Hello 2nd is 'o'!")
+}
+
 func (s *filterTest) Test_withErrorInWriter(c *C) {
 	s.writer.error = errors.New("Oops")
 	status, err := s.handler.ServeHTTP(s.writer, s.request)

integration_test.go

@@ -1,24 +1,28 @@
 package filter
 
 import (
-	"fmt"
-	"github.com/echocat/caddy-filter/utils/test"
 	. "github.com/echocat/gocheck-addons"
-	"github.com/mholt/caddy"
 	. "gopkg.in/check.v1"
+
+	"fmt"
 	"io/ioutil"
 	"net/http"
+	"github.com/echocat/caddy-filter/utils/test"
+	"github.com/mholt/caddy"
 
 	_ "github.com/mholt/caddy/caddyhttp/errors"
 	_ "github.com/mholt/caddy/caddyhttp/gzip"
 	_ "github.com/mholt/caddy/caddyhttp/markdown"
 	_ "github.com/mholt/caddy/caddyhttp/proxy"
 	_ "github.com/mholt/caddy/caddyhttp/root"
+	_ "github.com/mholt/caddy/caddyhttp/fastcgi"
+	_ "github.com/mholt/caddy/caddyhttp/log"
 )
 
 type integrationTest struct {
-	server *test.TestingServer
-	caddy  *caddy.Instance
+	httpServer *test.TestingHttpServer
+	fcgiServer *test.TestingFcgiServer
+	caddy      *caddy.Instance
 }
 
 func init() {
@@ -40,7 +44,7 @@ func (s *integrationTest) Test_staticWithGzip(c *C) {
 }
 
 func (s *integrationTest) Test_proxy(c *C) {
-	s.server = test.NewTestingServer(22770)
+	s.httpServer = test.NewTestingHttpServer(22770)
 
 	resp, err := http.Get("http://localhost:22780/default")
 	c.Assert(err, IsNil)
@@ -55,6 +59,22 @@ func (s *integrationTest) Test_proxyWithGzip(c *C) {
 	s.Test_proxy(c)
 }
 
+func (s *integrationTest) Test_fastcgi(c *C) {
+	s.fcgiServer = test.NewTestingFcgiServer(22790)
+
+	resp, err := http.Get("http://localhost:22780/index.cgi")
+	c.Assert(err, IsNil)
+
+	defer resp.Body.Close()
+	content, err := ioutil.ReadAll(resp.Body)
+	c.Assert(err, IsNil)
+	c.Assert(string(content), Contains, "<title>Hello replaced world!</title>")
+}
+
+func (s *integrationTest) Test_fastcgiWithGzip(c *C) {
+	s.Test_fastcgi(c)
+}
+
 func (s *integrationTest) Test_markdown(c *C) {
 	resp, err := http.Get("http://localhost:22780/index.md")
 	c.Assert(err, IsNil)
@@ -70,17 +90,23 @@ func (s *integrationTest) Test_markdownWithGzip(c *C) {
 }
 
 func (s *integrationTest) SetUpTest(c *C) {
-	c.Check(s.server, IsNil)
+	c.Check(s.httpServer, IsNil)
+	c.Check(s.fcgiServer, IsNil)
+	c.Check(s.caddy, IsNil)
 	s.caddy = test.NewTestingCaddy(fmt.Sprintf("%s.conf", c.TestName()))
 }
 
 func (s *integrationTest) TearDownTest(c *C) {
-	if s.server != nil {
-		s.server.Close()
+	if s.httpServer != nil {
+		s.httpServer.Close()
+	}
+	if s.fcgiServer != nil {
+		s.fcgiServer.Close()
 	}
 	if s.caddy != nil {
 		s.caddy.Stop()
 	}
-	s.server = nil
+	s.httpServer = nil
+	s.fcgiServer = nil
 	s.caddy = nil
 }

resources/test/integrationTest.Test_fastcgi.conf

@@ -0,0 +1,15 @@
+:22780 {
+  tls off
+  errors stdout
+  filter rule {
+    content_type "text/html.*"
+    search_pattern "Hello world!"
+    replacement "Hello replaced world!"
+  }
+  fastcgi / 127.0.0.1:22790 {
+    ext .cgi
+    split .cgi
+    index index.cgi
+    root resources/test/integrationTest.Test_fastcgi
+  }
+}

resources/test/integrationTest.Test_fastcgiWithGzip.conf

@@ -0,0 +1,16 @@
+:22780 {
+  tls off
+  errors stdout
+  gzip
+  filter rule {
+    content_type "text/html.*"
+    search_pattern "Hello world!"
+    replacement "Hello replaced world!"
+  }
+  fastcgi / 127.0.0.1:22790 {
+    ext .cgi
+    split .cgi
+    index index.cgi
+    root resources/test/integrationTest.Test_fastcgi
+  }
+}