Add Regex option for HeaderConfig

.gitignore

@@ -1,2 +1,3 @@
 vendor/
 goStatic
+.DS_Store

customHeaders.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 )
 
@@ -17,9 +18,32 @@ type HeaderConfigArray struct {
 
 // HeaderConfig is a single header rule specification
 type HeaderConfig struct {
+	Regex         string            `json:"regex"`
 	Path          string            `json:"path"`
 	FileExtension string            `json:"fileExtension"`
 	Headers       []HeaderDefiniton `json:"headers"`
+
+	CompiledRegex *regexp.Regexp
+}
+
+func (config *HeaderConfig) Init() (ok bool) {
+	if len(config.Regex) > 0 {
+		regex, err := regexp.Compile(config.Regex)
+
+		if err != nil {
+			fmt.Println("WARNING: Ignoring rule with regex error:", err)
+			fmt.Println("")
+			return
+		}
+		config.CompiledRegex = regex
+	}
+
+	ok = true
+	return
+}
+
+func (config *HeaderConfig) UsesRegex() bool {
+	return config.CompiledRegex != nil
 }
 
 // HeaderDefiniton is a key value pair of a specified header rule
@@ -39,8 +63,12 @@ func fileExists(filename string) bool {
 }
 
 func logHeaderConfig(config HeaderConfig) {
-	fmt.Println("Path: " + config.Path)
-	fmt.Println("FileExtension: " + config.FileExtension)
+	if config.UsesRegex() {
+		fmt.Println("Regex: " + config.Regex)
+	} else {
+		fmt.Println("Path: " + config.Path)
+		fmt.Println("FileExtension: " + config.FileExtension)
+	}
 
 	for j := 0; j < len(config.Headers); j++ {
 		headerRule := config.Headers[j]
@@ -56,7 +84,7 @@ func initHeaderConfig(headerConfigPath string) bool {
 	if fileExists(headerConfigPath) {
 		jsonFile, err := os.Open(headerConfigPath)
 		if err != nil {
-			fmt.Println("Cant't read header config file. Error:")
+			fmt.Println("Can't read header config file. Error:")
 			fmt.Println(err)
 		} else {
 			byteValue, _ := ioutil.ReadAll(jsonFile)
@@ -65,11 +93,22 @@ func initHeaderConfig(headerConfigPath string) bool {
 
 			if len(headerConfigs.Configs) > 0 {
 				headerConfigValid = true
+
+				// Only keep valid config entries.
+				keepers := make([]HeaderConfig, 0)
+				for _, configEntry := range headerConfigs.Configs {
+					ok := configEntry.Init()
+					if ok {
+						keepers = append(keepers, configEntry)
+					}
+				}
+
+				headerConfigs.Configs = keepers
+
+				// Print the config entries that are kept.
 				fmt.Println("Found header config file. Rules:")
 				fmt.Println("------------------------------")
-
-				for i := 0; i < len(headerConfigs.Configs); i++ {
-					configEntry := headerConfigs.Configs[i]
+				for _, configEntry := range headerConfigs.Configs {
 					logHeaderConfig(configEntry)
 				}
 			} else {
@@ -89,11 +128,19 @@ func customHeadersMiddleware(next http.Handler) http.Handler {
 
 		for i := 0; i < len(headerConfigs.Configs); i++ {
 			configEntry := headerConfigs.Configs[i]
+			var matches bool
 
-			fileMatch := configEntry.FileExtension == "*" || reqFileExtension == "."+configEntry.FileExtension
-			pathMatch := configEntry.Path == "*" || strings.HasPrefix(r.URL.Path, configEntry.Path)
+			if configEntry.UsesRegex() {
+				matches = configEntry.CompiledRegex.MatchString(r.URL.Path)
+			} else {
+				matches =
+					// Check if the file extension matches.
+					(configEntry.FileExtension == "*" || reqFileExtension == "."+configEntry.FileExtension) &&
+						// Check if the path matches.
+						(configEntry.Path == "*" || strings.HasPrefix(r.URL.Path, configEntry.Path))
+			}
 
-			if fileMatch && pathMatch {
+			if matches {
 				for j := 0; j < len(configEntry.Headers); j++ {
 					headerEntry := configEntry.Headers[j]
 					w.Header().Set(headerEntry.Key, headerEntry.Value)

customHeaders_test.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHeaderConfigWithValidRegex(t *testing.T) {
+	assert := assert.New(t)
+	config := HeaderConfig{Regex: "/$"}
+
+	ok := config.Init()
+	assert.True(ok)
+	assert.NotNil(config.CompiledRegex)
+	assert.True(config.UsesRegex())
+}
+
+func TestHeaderConfigWithInvalidRegex(t *testing.T) {
+	assert := assert.New(t)
+	config := HeaderConfig{Regex: "["}
+
+	ok := config.Init()
+	assert.False(ok)
+	assert.Nil(config.CompiledRegex)
+}
+
+func TestHeaderConfigWithoutRegex(t *testing.T) {
+	assert := assert.New(t)
+	config := HeaderConfig{
+		Path:          "/page-data",
+		FileExtension: "json",
+	}
+
+	ok := config.Init()
+	assert.True(ok)
+	assert.Nil(config.CompiledRegex)
+	assert.False(config.UsesRegex())
+}

docs/header-config.md

@@ -4,7 +4,44 @@ With the header config, you can specify custom [HTTP Header](https://developer.m
 
 ## Config
 
-You have to create a JSON file that serves as a config. The JSON must contain a `configs` array. For every entry, you can specify a certain path that must be matched as well as a file extension. You can use the `*` symbol to use the config entry for any path or filename. Note that the path option only matches the requested path from the start. Thatswhy you have to start with a `/` and can use paths like `/files/static/css`. The `headers` array includes a key-value pair of the actual header rule. The headers are not parsed so double check your spelling and test your site.
+You have to create a JSON file that serves as a config. The JSON must contain a `configs` array. For every entry, you can specify the rule in one of two ways:
+
+1. A regular expression that the path must meet, e.g.:
+
+```json
+{
+  "regex": "/$",
+  "headers": [
+    {
+      "key": "cache-control",
+      "value": "no-cache, no-store, must-revalidate"
+    }
+  ]
+}
+```
+
+This rule would match any path ending in `/` which is useful if you never want to cache the `index.html` that a directory leads to.
+
+2. You may specify a combination of `path` and `fileExtension`:
+
+```json
+{
+  "path": "*",
+  "fileExtension": "html",
+  "headers": [
+    {
+      "key": "cache-control",
+      "value": "public, max-age=0, must-revalidate"
+    },
+    {
+      "key": "Strict-Transport-Security",
+      "value": "max-age=31536000; includeSubDomains;"
+    }
+  ]
+}
+```
+
+You can use the `*` symbol to use the config entry for any path or filename. Note that the path option only matches the requested path from the start. That's why you have to start with a `/` and can use paths like `/files/static/css`. The `headers` array includes a key-value pair of the actual header rule. The headers are not parsed so double check your spelling and test your site.
 
 The created JSON config has to be mounted into the container via a volume into `/config/headerConfig.json` per default. When this file does not exist inside the container, the header middleware will not be active.
 

go.mod

@@ -1,3 +1,5 @@
 module github.com/PierreZ/goStatic
 
 go 1.16
+
+require github.com/stretchr/testify v1.7.0

go.sum

@@ -0,0 +1,11 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=