Unify connection handling

3 files changed, 104 insertions, 43 deletions

diff --git a/internal/feed/mail.go b/internal/feed/mail.go
index 3cb442e..0360e10 100644
--- a/internal/feed/mail.go
+++ b/internal/feed/mail.go
@@ -7,7 +7,6 @@ import (
 	"io"
 	"io/ioutil"
 	"mime"
-	"net/http"
 	"net/url"
 	"path"
 	"strings"
@@ -19,6 +18,7 @@ import (
 	"github.com/gabriel-vasile/mimetype"
 
 	"github.com/Necoro/feed2imap-go/internal/feed/template"
+	"github.com/Necoro/feed2imap-go/internal/http"
 	"github.com/Necoro/feed2imap-go/internal/msg"
 	"github.com/Necoro/feed2imap-go/pkg/config"
 	"github.com/Necoro/feed2imap-go/pkg/log"
@@ -193,12 +193,12 @@ func (feed *Feed) Messages() (msg.Messages, error) {
 	return mails, nil
 }
 
-func getImage(src string, client *http.Client) ([]byte, string, error) {
-	resp, err := client.Get(src)
+func getImage(src string, timeout int, disableTLS bool) ([]byte, string, error) {
+	resp, cancel, err := http.Get(src, timeout, disableTLS)
 	if err != nil {
 		return nil, "", fmt.Errorf("fetching from '%s': %w", src, err)
 	}
-	defer resp.Body.Close()
+	defer cancel()
 
 	img, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
@@ -270,7 +270,7 @@ func (item *item) buildBody() {
 			return
 		}
 
-		srcUrl,err := url.Parse(src)
+		srcUrl, err := url.Parse(src)
 		if err != nil {
 			log.Errorf("Feed %s: Item %s: Error parsing URL '%s' embedded in item: %s",
 				feed.Name, item.Item.Link, src, err)
@@ -278,7 +278,7 @@ func (item *item) buildBody() {
 		}
 		imgUrl := feedUrl.ResolveReference(srcUrl)
 
-		img, mime, err := getImage(imgUrl.String(), httpClient(feed.NoTLS))
+		img, mime, err := getImage(imgUrl.String(), feed.Global.Timeout, feed.NoTLS)
 		if err != nil {
 			log.Errorf("Feed %s: Item %s: Error fetching image: %s",
 				feed.Name, item.Item.Link, err)
diff --git a/internal/feed/parse.go b/internal/feed/parse.go
index 1ba90fd..a8f705a 100644
--- a/internal/feed/parse.go
+++ b/internal/feed/parse.go
@@ -1,57 +1,30 @@
 package feed
 
 import (
-	ctxt "context"
-	"crypto/tls"
 	"fmt"
-	"net/http"
-	"time"
 
 	"github.com/google/uuid"
 	"github.com/mmcdole/gofeed"
 
+	"github.com/Necoro/feed2imap-go/internal/http"
 	"github.com/Necoro/feed2imap-go/pkg/log"
 )
 
-// share HTTP clients
-var (
-	stdHTTPClient    *http.Client
-	unsafeHTTPClient *http.Client
-)
-
-func init() {
-	// std
-	stdHTTPClient = &http.Client{Transport: http.DefaultTransport}
-
-	// unsafe
-	tlsConfig := &tls.Config{InsecureSkipVerify: true}
-	transport := http.DefaultTransport.(*http.Transport).Clone()
-	transport.TLSClientConfig = tlsConfig
-	unsafeHTTPClient = &http.Client{Transport: transport}
-}
-
-func context(timeout int) (ctxt.Context, ctxt.CancelFunc) {
-	return ctxt.WithTimeout(ctxt.Background(), time.Duration(timeout)*time.Second)
-}
-
-func httpClient(disableTLS bool) *http.Client {
-	if disableTLS {
-		return unsafeHTTPClient
-	}
-	return stdHTTPClient
-}
-
 func (feed *Feed) parse() error {
-	ctx, cancel := context(feed.Global.Timeout)
-	defer cancel()
-
 	fp := gofeed.NewParser()
-	fp.Client = httpClient(feed.NoTLS)
 
-	parsedFeed, err := fp.ParseURLWithContext(feed.Url, ctx)
+	// we do not use the http support in gofeed, so that we can control the behavior of http requests
+	// and ensure it to be the same in all places
+	resp, cancel, err := http.Get(feed.Url, feed.Global.Timeout, feed.NoTLS)
 	if err != nil {
 		return fmt.Errorf("while fetching %s from %s: %w", feed.Name, feed.Url, err)
 	}
+	defer cancel() // includes resp.Body.Close
+
+	parsedFeed, err := fp.Parse(resp.Body)
+	if err != nil {
+		return fmt.Errorf("parsing feed '%s': %w", feed.Name, err)
+	}
 
 	feed.feed = parsedFeed
 	feed.items = make([]item, len(parsedFeed.Items))
diff --git a/internal/http/client.go b/internal/http/client.go
new file mode 100644
index 0000000..c9af26e
--- /dev/null
+++ b/internal/http/client.go
@@ -0,0 +1,88 @@
+package http
+
+import (
+	ctxt "context"
+	"crypto/tls"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// share HTTP clients
+var (
+	stdClient    *http.Client
+	unsafeClient *http.Client
+)
+
+// Error represents an HTTP error returned by a server.
+type Error struct {
+	StatusCode int
+	Status     string
+}
+
+func (err Error) Error() string {
+	return fmt.Sprintf("http error: %s", err.Status)
+}
+
+func init() {
+	// std
+	stdClient = &http.Client{Transport: http.DefaultTransport}
+
+	// unsafe
+	tlsConfig := &tls.Config{InsecureSkipVerify: true}
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	transport.TLSClientConfig = tlsConfig
+	unsafeClient = &http.Client{Transport: transport}
+}
+
+func context(timeout int) (ctxt.Context, ctxt.CancelFunc) {
+	return ctxt.WithTimeout(ctxt.Background(), time.Duration(timeout)*time.Second)
+}
+
+func client(disableTLS bool) *http.Client {
+	if disableTLS {
+		return unsafeClient
+	}
+	return stdClient
+}
+
+var noop ctxt.CancelFunc = func() {}
+
+func Get(url string, timeout int, disableTLS bool) (resp *http.Response, cancel ctxt.CancelFunc, err error) {
+	prematureExit := true
+	ctx, ctxCancel := context(timeout)
+
+	cancel = func() {
+		if resp != nil {
+			_ = resp.Body.Close()
+		}
+		ctxCancel()
+	}
+
+	defer func() {
+		if prematureExit {
+			cancel()
+		}
+	}()
+
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, noop, err
+	}
+	req.Header.Set("User-Agent", "Feed2Imap-Go/1.0")
+
+	resp, err = client(disableTLS).Do(req)
+	if err != nil {
+		return nil, noop, err
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return nil, noop, Error{
+			StatusCode: resp.StatusCode,
+			Status:     resp.Status,
+		}
+	}
+
+	prematureExit = false
+	return resp, cancel, nil
+}