feat: add "terminus" -plugin for resolving redirects (#10)

* feat: add "terminus" -plugin for resolving redirects

* ci(lint): use golangci-lint-action v4

* feat: allow disabling individual plugins using "isDisabled" configuration option

* feat: make terminus -plugin configurable

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
         with:
           go-version: '1.21'
       - name: golangci-lint
-        uses: golangci/golangci-lint-action@v3
+        uses: golangci/golangci-lint-action@v4
         with:
           # Require: The version of golangci-lint to use.
           # When `install-mode` is `binary` (default) the value can be v1.2 or v1.2.3 or `latest` to use the latest version.

.goreleaser.yaml

@@ -35,6 +35,24 @@ builds:
       - -X main.commitSHA={{.FullCommit}}
       - -X main.buildDate={{.Date}}
 
+  - id: "terminus-plugin"
+    binary: "plugins/terminus.so"
+    buildmode: plugin
+    no_main_check: true
+    goos:
+      - linux
+    goarch:
+      - amd64
+    main: ./plugins/terminus/
+    flags:
+      - -trimpath
+      - -buildvcs=false
+    ldflags:
+      - -s -w
+      - -X main.version={{.Version}}
+      - -X main.commitSHA={{.FullCommit}}
+      - -X main.buildDate={{.Date}}
+
 nfpms:
   - meta: true
     package_name: linkquisition
@@ -53,6 +71,8 @@ nfpms:
         dst: /usr/bin/linkquisition
       - src: ./dist/unwrap-plugin_{{ .Os }}_{{ .Arch }}_v1/plugins/unwrap.so
         dst: /usr/lib/linkquisition/plugins/unwrap.so
+      - src: ./dist/terminus-plugin_{{ .Os }}_{{ .Arch }}_v1/plugins/terminus.so
+        dst: /usr/lib/linkquisition/plugins/terminus.so
       - src: package/linux
         dst: /
         type: tree

README.md

@@ -24,6 +24,7 @@ Motivation behind this project is:
     - regular expression (e.g. `.*\.example\.com`)
   - Hide a browser from the list
   - Manually add a browser to the list (for example, to open a URL in a different profile)
+  - Remember the choice for given site
 - keyboard-shortcuts
   - `Enter` to open the URL in the default browser
   - `Ctrl+C` to just copy the URL to clipboard and close the window

Taskfile.build.yml

@@ -34,6 +34,7 @@ tasks:
     cmds:
       - mkdir -p package/linux/usr/lib/linkquisition/plugins
       - go build -buildmode=plugin -o package/linux/usr/lib/linkquisition/plugins/unwrap.so ./plugins/unwrap/unwrap.go
+      - go build -buildmode=plugin -o package/linux/usr/lib/linkquisition/plugins/terminus.so ./plugins/terminus/terminus.go
 
   clean:
     cmds:

cmd/application.go

@@ -68,6 +68,11 @@ func setupPlugins(
 	var plugins []linkquisition.Plugin
 
 	for _, pluginSettings := range settings.Plugins {
+		if pluginSettings.IsDisabled {
+			logger.Debug("Plugin is disabled by configuration directive", "plugin", pluginSettings.Path)
+			continue
+		}
+
 		pluginPath := pluginSettings.Path
 		if !strings.HasSuffix(pluginPath, ".so") {
 			pluginPath += ".so"

mock/http.go

@@ -0,0 +1,11 @@
+package mock
+
+import "net/http"
+
+type RoundTripper struct {
+	RoundTripFunc func(r *http.Request) (*http.Response, error)
+}
+
+func (rt *RoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
+	return rt.RoundTripFunc(r)
+}

plugins/README.md

@@ -51,6 +51,33 @@ In the above example, the `requireBrowserMatchToUnwrap` -setting is set to `true
 unwrap the links if there is a matching browser-rule for that URL and all the rest of the URLs are opened with full
 Evergreen-protected URL.
 
+## [Terminus](./terminus/terminus.go) -plugin
+
+This plugin can be used to resolve redirects before processing actual rules or showing the browser picker dialog to the
+user.
+
+The plugin is configurable in terms of how many redirect-"jumps" to follow and the time-limit how long the requests are
+allowed to take before giving up. Here's an example:
+
+```json
+{
+  "browsers": [
+    ...
+  ],
+  "plugins": [
+    {
+      "path": "terminus.so",
+      "isDisabled": false,
+      "settings": {
+        "maxRedirects": 10,
+        "requestTimeout": "2s"
+      }
+    }
+  ]
+}
+
+```
+
 ## Developing plugins
 
 As stated before, the plugins-feature is experimental, the API is not stable and therefore subject to change. However,

plugins/terminus/terminus.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/mitchellh/mapstructure"
+
+	"github.com/strobotti/linkquisition"
+)
+
+type TerminusPluginSettings struct {
+	MaxRedirects   int    `json:"maxRedirects"`
+	RequestTimeout string `json:"requestTimeout"`
+}
+
+var _ linkquisition.Plugin = (*terminus)(nil)
+
+type terminus struct {
+	MaxRedirects    int
+	Client          *http.Client
+	RequestTimeout  time.Duration
+	serviceProvider linkquisition.PluginServiceProvider
+}
+
+func (p *terminus) Setup(serviceProvider linkquisition.PluginServiceProvider, config map[string]interface{}) {
+	p.MaxRedirects = 5
+	p.RequestTimeout = time.Millisecond * 2000
+
+	var settings TerminusPluginSettings
+	if err := mapstructure.Decode(config, &settings); err != nil {
+		serviceProvider.GetLogger().Warn("error decoding settings", "error", err.Error(), "plugin", "terminus")
+	} else {
+		if settings.MaxRedirects > 0 {
+			p.MaxRedirects = settings.MaxRedirects
+		}
+		if settings.RequestTimeout != "" {
+			if timeout, err := time.ParseDuration(settings.RequestTimeout); err != nil {
+				serviceProvider.GetLogger().Warn(
+					"requestTimeout configuration option is malformed", "error", err.Error(), "plugin",
+					"terminus",
+				)
+			} else {
+				p.RequestTimeout = timeout
+			}
+		}
+	}
+
+	p.serviceProvider = serviceProvider
+	p.Client = &http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+}
+
+func (p *terminus) ModifyUrl(url string) string {
+	newUrl := url
+
+	ctx, cancel := context.WithTimeout(context.Background(), p.RequestTimeout)
+	defer cancel()
+
+	for i := 0; i < p.MaxRedirects; i++ {
+		req, _ := http.NewRequestWithContext(ctx, http.MethodHead, newUrl, http.NoBody)
+		req.Header.Set("User-Agent", "linkquisition")
+		resp, err := p.Client.Do(req)
+		if err != nil {
+			p.serviceProvider.GetLogger().Warn(fmt.Sprintf("error requesting HEAD %s", newUrl), "error", err.Error(), "plugin", "terminus")
+			return newUrl
+		}
+
+		if resp.Body != nil {
+			_ = resp.Body.Close()
+		}
+
+		if resp.StatusCode < 300 || resp.StatusCode >= 400 {
+			// we got a non-redirect response, so we have reached our final destination
+			break
+		}
+
+		location := resp.Header.Get("Location")
+
+		if location == "" {
+			// for whatever reason the location -header doesn't contain a URL; skip
+			p.serviceProvider.GetLogger().Warn(fmt.Sprintf("no location-header for HEAD %s", newUrl), "plugin", "terminus")
+			break
+		}
+
+		p.serviceProvider.GetLogger().Debug(
+			fmt.Sprintf("following a redirect for %s", newUrl), "location", location, "plugin", "terminus",
+		)
+
+		newUrl = location
+	}
+
+	return newUrl
+}
+
+var Plugin terminus

plugins/terminus/terminus_test.go

@@ -0,0 +1,111 @@
+package main_test
+
+import (
+	"log/slog"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/strobotti/linkquisition"
+
+	"github.com/strobotti/linkquisition/mock"
+	. "github.com/strobotti/linkquisition/plugins/terminus"
+)
+
+func TestTerminus_ModifyUrl(t *testing.T) {
+	mockIoWriter := mock.Writer{
+		WriteFunc: func(p []byte) (n int, err error) {
+			return len(p), nil
+		},
+	}
+	logger := slog.New(slog.NewTextHandler(mockIoWriter, nil))
+
+	for _, tt := range []struct {
+		name          string
+		inputUrl      string
+		expectedUrl   string
+		locations     map[string]string
+		responseCodes map[string]int
+	}{
+		{
+			name:        "original url should be returned if no redirect is detected",
+			inputUrl:    "https://www.example.com/some/thing?here=again",
+			expectedUrl: "https://www.example.com/some/thing?here=again",
+		},
+		{
+			name:        "a url from location -header should be returned if a redirect is detected",
+			inputUrl:    "https://www.example.com/some/thing?here=again",
+			expectedUrl: "https://www2.example.com/some/thing?here=again",
+			locations: map[string]string{
+				"https://www.example.com/some/thing?here=again": "https://www2.example.com/some/thing?here=again",
+			},
+			responseCodes: map[string]int{
+				"https://www.example.com/some/thing?here=again": http.StatusMultipleChoices,
+			},
+		},
+		{
+			name:        "a chain of redirects works as expected",
+			inputUrl:    "https://www.example.com/some/thing?here=again",
+			expectedUrl: "https://www3.example.com/some/thing?here=again",
+			locations: map[string]string{
+				"https://www.example.com/some/thing?here=again":  "https://www2.example.com/some/thing?here=again",
+				"https://www2.example.com/some/thing?here=again": "https://www3.example.com/some/thing?here=again",
+			},
+			responseCodes: map[string]int{
+				"https://www.example.com/some/thing?here=again":  http.StatusMultipleChoices,
+				"https://www2.example.com/some/thing?here=again": http.StatusMultipleChoices,
+			},
+		},
+		{
+			name:        "a chain of redirects is capped to 5 hops",
+			inputUrl:    "https://www.example.com/some/thing?here=again",
+			expectedUrl: "https://www6.example.com/some/thing?here=again",
+			locations: map[string]string{
+				"https://www.example.com/some/thing?here=again":  "https://www2.example.com/some/thing?here=again",
+				"https://www2.example.com/some/thing?here=again": "https://www3.example.com/some/thing?here=again",
+				"https://www3.example.com/some/thing?here=again": "https://www4.example.com/some/thing?here=again",
+				"https://www4.example.com/some/thing?here=again": "https://www5.example.com/some/thing?here=again",
+				"https://www5.example.com/some/thing?here=again": "https://www6.example.com/some/thing?here=again",
+				"https://www6.example.com/some/thing?here=again": "https://www7.example.com/some/thing?here=again",
+				"https://www7.example.com/some/thing?here=again": "https://www8.example.com/some/thing?here=again",
+			},
+			responseCodes: map[string]int{
+				"https://www.example.com/some/thing?here=again":  http.StatusMultipleChoices,
+				"https://www2.example.com/some/thing?here=again": http.StatusMultipleChoices,
+				"https://www3.example.com/some/thing?here=again": http.StatusMultipleChoices,
+				"https://www4.example.com/some/thing?here=again": http.StatusMultipleChoices,
+				"https://www5.example.com/some/thing?here=again": http.StatusMultipleChoices,
+				"https://www6.example.com/some/thing?here=again": http.StatusMultipleChoices,
+				"https://www7.example.com/some/thing?here=again": http.StatusMultipleChoices,
+			},
+		},
+	} {
+		t.Run(
+			tt.name, func(t *testing.T) {
+				testedPlugin := Plugin
+
+				provider := linkquisition.NewPluginServiceProvider(logger, &linkquisition.Settings{})
+				testedPlugin.Setup(provider, map[string]interface{}{})
+				testedPlugin.Client.Transport = &mock.RoundTripper{
+					RoundTripFunc: func(r *http.Request) (*http.Response, error) {
+						resp := &http.Response{
+							StatusCode: http.StatusOK,
+							Header:     http.Header{},
+						}
+
+						if code, ok := tt.responseCodes[r.URL.String()]; ok {
+							resp.StatusCode = code
+						}
+						if location, ok := tt.locations[r.URL.String()]; ok {
+							resp.Header.Set("Location", location)
+						}
+
+						return resp, nil
+					},
+				}
+
+				assert.Equal(t, tt.expectedUrl, testedPlugin.ModifyUrl(tt.inputUrl))
+			},
+		)
+	}
+}

settings.go

@@ -70,7 +70,11 @@ func (s *BrowserSettings) MatchesUrl(u string) bool {
 
 type PluginSettings struct {
 	// Path is the path to the plugin binary
-	Path     string                 `json:"path"`
+	Path string `json:"path"`
+
+	// IsDisabled allows temporarily disabling individual plugins
+	IsDisabled bool `json:"isDisabled"`
+
 	Settings map[string]interface{} `json:"settings,omitempty"`
 }