feat: add redirect option

Author: marjune163

.editorconfig

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+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+max_line_length = 200
+indent_style = tab
+indent_size = 4
+charset = utf-8
+

.gitignore

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+.*/

LICENSE

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+MIT License
+
+Copyright (c) 2022 MJ PC Lab
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Extra HTTP File Server
+
+Extra HTTP File Server is based on Go HTTP File Server, with extra features.
+It provides frequently used features for a simple static website.
+
+# Different to Go HTTP File Server
+
+## Code base
+
+Based on Go HTTP File Server's main branch, dropped support for legacy Go version.
+This means it is impossible to use legacy Go version to compile binaries for legacy systems, e.g. Windows XP.
+
+## New options
+
+```
+--redirect <separator><match><separator><replace>[<separator><status_code>]
+    Perform an HTTP redirect when request URL (in the form of "/request/path?param=value")
+    is matched by regular expression `match`.
+
+    The redirect target is specified by `replace`.
+    Use `$0` to represent the whole match in `match`.
+    use `$1` - `$9` to represent sub matches in `match`.
+
+    Optional `status_code` specifies HTTP redirect code. defaults to 301.
+```
+
+## Examples
+
+Perform redirect according to `redirect` param:
+
+```sh
+# when requesting http://localhost:8080/redirect/www.example.com, redirect to https://www.example.com
+ehfs -l 8080 -r /path/to/share --redirect '#/redirect/(.*)#https://$1'
+```

README.zh-CN.md

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+# Extra HTTP File Server
+
+Extra HTTP File Server基于Go HTTP File Server，附带额外功能。
+它为简单静态网站提供了常用的功能。
+
+# 与Go HTTP File Server的区别
+
+## 代码库
+
+基于Go HTTP File Server主分支，放弃了对旧版Go的支持。
+这意味着不能使用旧的Go版本来编译较老系统的二进制文件，例如Windows XP。
+
+## 新增选项
+
+```
+--redirect <分隔符><match><separator><分隔符>[<separator><status_code>]
+    当请求的URL（“/request/path?param=value”的形式）匹配正则表达式`match`时，
+    执行HTTP重定向。
+
+    重定向目标由`replace`指定。
+    使用`$0`表示`match`的完整匹配。
+    使用`$1`-`$9`来表示`match`中的子匹配。
+
+    可选的`status_code`指定HTTP重定向代码。 默认为301。
+```
+
+## 举例
+
+根据`redirect`参数执行重定向：
+
+```sh
+# 当请求 http://localhost:8080/redirect/www.example.com时，重定向到https://www.example.com
+ehfs -l 8080 -r /path/to/share --redirect '#/redirect/(.*)#https://$1'
+```

go.mod

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+module mjpclab.dev/ehfs
+
+go 1.19
+
+require mjpclab.dev/ghfs v1.15.2

go.sum

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+mjpclab.dev/ghfs v1.15.2 h1:MucVnmAI62js3fY9TYdwcha+V36Mj1N+Cytk7r5W4FM=
+mjpclab.dev/ghfs v1.15.2/go.mod h1:mwJoteyRIJ9QXBxai58QmsHvTb29GFBbaumgZWpxxqk=

src/main.go

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+package main
+
+import (
+	"errors"
+	"mjpclab.dev/ehfs/src/middleware"
+	"mjpclab.dev/ehfs/src/param"
+	"mjpclab.dev/ehfs/src/version"
+	"mjpclab.dev/ghfs/src/app"
+	"mjpclab.dev/ghfs/src/serverError"
+	"mjpclab.dev/ghfs/src/setting"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func cleanupOnEnd(appInst *app.App) {
+	chSignal := make(chan os.Signal)
+	signal.Notify(chSignal, syscall.SIGINT, syscall.SIGTERM)
+
+	go func() {
+		<-chSignal
+		appInst.Shutdown()
+		os.Exit(0)
+	}()
+}
+
+func reopenLogOnHup(appInst *app.App) {
+	chSignal := make(chan os.Signal)
+	signal.Notify(chSignal, syscall.SIGHUP)
+
+	go func() {
+		for range chSignal {
+			errs := appInst.ReOpenLog()
+			serverError.CheckFatal(errs...)
+		}
+	}()
+}
+
+func main() {
+	// params
+	baseParams, params, printVersion, printHelp, errs := param.ParseFromCli()
+	serverError.CheckFatal(errs...)
+	if printVersion {
+		version.PrintVersion()
+		os.Exit(0)
+	}
+	if printHelp {
+		param.PrintHelp()
+		os.Exit(0)
+	}
+
+	// apply middlewares
+	errs = middleware.ApplyMiddlewares(baseParams, params)
+	serverError.CheckFatal(errs...)
+
+	// setting
+	setting := setting.ParseFromEnv()
+
+	// app
+	appInst, errs := app.NewApp(baseParams, setting)
+	serverError.CheckFatal(errs...)
+	if appInst == nil {
+		serverError.CheckFatal(errors.New("failed to create application instance"))
+	}
+
+	cleanupOnEnd(appInst)
+	reopenLogOnHup(appInst)
+	errs = appInst.Open()
+	serverError.CheckFatal(errs...)
+	appInst.Shutdown()
+}

src/middleware/main.go

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+package middleware
+
+import (
+	"errors"
+	"mjpclab.dev/ehfs/src/param"
+	"mjpclab.dev/ghfs/src/middleware"
+	baseParam "mjpclab.dev/ghfs/src/param"
+	"mjpclab.dev/ghfs/src/serverError"
+)
+
+var errInvalidParamValue = errors.New("invalid param value")
+var errParamCountNotMatch = errors.New("base-param count is not equal to param count")
+
+func ParamToMiddlewares(baseParam *baseParam.Param, param *param.Param) (preMids, postMids []middleware.Middleware, errs []error) {
+	// redirects
+	for i := range param.Redirects {
+		mid, err := getRedirectMiddleware(param.Redirects[i])
+		errs = serverError.AppendError(errs, err)
+		if mid != nil {
+			preMids = append(preMids, mid)
+		}
+	}
+
+	return
+}
+
+func ApplyMiddlewares(baseParams []*baseParam.Param, params []*param.Param) (errs []error) {
+	if len(baseParams) != len(params) {
+		return []error{errParamCountNotMatch}
+	}
+
+	for i := range baseParams {
+		var es []error
+		baseParams[i].PreMiddlewares, baseParams[i].PostMiddlewares, es = ParamToMiddlewares(baseParams[i], params[i])
+		errs = append(errs, es...)
+	}
+
+	return
+}

src/middleware/redirect.go

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+package middleware
+
+import (
+	"mjpclab.dev/ghfs/src/middleware"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+func getRedirectMiddleware(arg [3]string) (middleware.Middleware, error) {
+	var err error
+	var reMatch *regexp.Regexp
+	var replace string
+	var code int
+
+	reMatch, err = regexp.Compile(arg[0])
+	if err != nil {
+		return nil, err
+	}
+	replace = arg[1]
+	code, err = strconv.Atoi(arg[2])
+	if err != nil {
+		return nil, err
+	}
+
+	return func(w http.ResponseWriter, r *http.Request, context *middleware.Context) (processed bool) {
+		requestURI := r.URL.RequestURI() // request uri without prefix path
+		if !reMatch.MatchString(requestURI) {
+			return false
+		}
+		matches := reMatch.FindStringSubmatch(requestURI)
+		if len(matches) > 10 {
+			matches = matches[:10]
+		}
+
+		target := replace
+		for i := range matches {
+			target = strings.ReplaceAll(target, "$"+strconv.Itoa(i), matches[i])
+		}
+		if len(target) == 0 {
+			target = "/"
+		}
+
+		u, err := url.Parse(target)
+		if err != nil ||
+			((len(u.Host) == 0 || u.Host == r.Host) && u.RequestURI() == r.RequestURI) {
+			w.WriteHeader(http.StatusBadRequest)
+		} else {
+			http.Redirect(w, r, u.String(), code)
+		}
+		return true
+	}, nil
+}

src/middleware/redirect_test.go

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+package middleware
+
+import (
+	"mjpclab.dev/ghfs/src/middleware"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestRedirect(t *testing.T) {
+	mid, err := getRedirectMiddleware([3]string{`\?goto=(.*)`, "$1", "307"})
+	if err != nil {
+		t.FailNow()
+	}
+
+	var w *httptest.ResponseRecorder
+	var r *http.Request
+	var result middleware.ProcessResult
+	var location string
+
+	w = httptest.NewRecorder()
+	r = httptest.NewRequest(http.MethodGet, "/abc", nil)
+	result = mid(w, r, &middleware.Context{})
+	if result != middleware.GoNext {
+		t.Error(result)
+	}
+	if w.Code != 200 {
+		t.Error(w.Code)
+	}
+	location = w.Header().Get("Location")
+	if location != "" {
+		t.Error(location)
+	}
+
+	w = httptest.NewRecorder()
+	r = httptest.NewRequest(http.MethodGet, "/abc?goto=/", nil)
+	result = mid(w, r, &middleware.Context{})
+	if result != middleware.Processed {
+		t.Error(result)
+	}
+	if w.Code != 307 {
+		t.Error(w.Code)
+	}
+	location = w.Header().Get("Location")
+	if location != "/" {
+		t.Error(location)
+	}
+
+	w = httptest.NewRecorder()
+	r = httptest.NewRequest(http.MethodGet, "/abc?goto=http://www.example.com/", nil)
+	result = mid(w, r, &middleware.Context{})
+	if result != middleware.Processed {
+		t.Error(result)
+	}
+	if w.Code != 307 {
+		t.Error(w.Code)
+	}
+	location = w.Header().Get("Location")
+	if location != "http://www.example.com/" {
+		t.Error(location)
+	}
+}