diff options
Diffstat (limited to 'replacer.go')
| -rw-r--r-- | replacer.go | 107 |
1 files changed, 92 insertions, 15 deletions
diff --git a/replacer.go b/replacer.go index 2ad5b8bcb..e5d2913e9 100644 --- a/replacer.go +++ b/replacer.go @@ -16,6 +16,7 @@ package caddy import ( "fmt" + "io" "net/http" "os" "path/filepath" @@ -24,6 +25,8 @@ import ( "strings" "sync" "time" + + "go.uber.org/zap" ) // NewReplacer returns a new Replacer. @@ -32,9 +35,10 @@ func NewReplacer() *Replacer { static: make(map[string]any), mapMutex: &sync.RWMutex{}, } - rep.providers = []ReplacerFunc{ - globalDefaultReplacements, - rep.fromStatic, + rep.providers = []replacementProvider{ + globalDefaultReplacementProvider{}, + fileReplacementProvider{}, + ReplacerFunc(rep.fromStatic), } return rep } @@ -46,8 +50,8 @@ func NewEmptyReplacer() *Replacer { static: make(map[string]any), mapMutex: &sync.RWMutex{}, } - rep.providers = []ReplacerFunc{ - rep.fromStatic, + rep.providers = []replacementProvider{ + ReplacerFunc(rep.fromStatic), } return rep } @@ -56,10 +60,25 @@ func NewEmptyReplacer() *Replacer { // A default/empty Replacer is not valid; // use NewReplacer to make one. type Replacer struct { - providers []ReplacerFunc + providers []replacementProvider + static map[string]any + mapMutex *sync.RWMutex +} - static map[string]any - mapMutex *sync.RWMutex +// WithoutFile returns a copy of the current Replacer +// without support for the {file.*} placeholder, which +// may be unsafe in some contexts. +// +// EXPERIMENTAL: Subject to change or removal. +func (r *Replacer) WithoutFile() *Replacer { + rep := &Replacer{static: r.static} + for _, v := range r.providers { + if _, ok := v.(fileReplacementProvider); ok { + continue + } + rep.providers = append(rep.providers, v) + } + return rep } // Map adds mapFunc to the list of value providers. @@ -79,7 +98,7 @@ func (r *Replacer) Set(variable string, value any) { // the value and whether the variable was known. func (r *Replacer) Get(variable string) (any, bool) { for _, mapFunc := range r.providers { - if val, ok := mapFunc(variable); ok { + if val, ok := mapFunc.replace(variable); ok { return val, true } } @@ -298,14 +317,52 @@ func ToString(val any) string { } } -// ReplacerFunc is a function that returns a replacement -// for the given key along with true if the function is able -// to service that key (even if the value is blank). If the -// function does not recognize the key, false should be -// returned. +// ReplacerFunc is a function that returns a replacement for the +// given key along with true if the function is able to service +// that key (even if the value is blank). If the function does +// not recognize the key, false should be returned. type ReplacerFunc func(key string) (any, bool) -func globalDefaultReplacements(key string) (any, bool) { +func (f ReplacerFunc) replace(key string) (any, bool) { + return f(key) +} + +// replacementProvider is a type that can provide replacements +// for placeholders. Allows for type assertion to determine +// which type of provider it is. +type replacementProvider interface { + replace(key string) (any, bool) +} + +// fileReplacementsProvider handles {file.*} replacements, +// reading a file from disk and replacing with its contents. +type fileReplacementProvider struct{} + +func (f fileReplacementProvider) replace(key string) (any, bool) { + if !strings.HasPrefix(key, filePrefix) { + return nil, false + } + + filename := key[len(filePrefix):] + maxSize := 1024 * 1024 + body, err := readFileIntoBuffer(filename, maxSize) + if err != nil { + wd, _ := os.Getwd() + Log().Error("placeholder: failed to read file", + zap.String("file", filename), + zap.String("working_dir", wd), + zap.Error(err)) + return nil, true + } + return string(body), true +} + +// globalDefaultReplacementsProvider handles replacements +// that can be used in any context, such as system variables, +// time, or environment variables. +type globalDefaultReplacementProvider struct{} + +func (f globalDefaultReplacementProvider) replace(key string) (any, bool) { // check environment variable const envPrefix = "env." if strings.HasPrefix(key, envPrefix) { @@ -347,6 +404,24 @@ func globalDefaultReplacements(key string) (any, bool) { return nil, false } +// readFileIntoBuffer reads the file at filePath into a size limited buffer. +func readFileIntoBuffer(filename string, size int) ([]byte, error) { + file, err := os.Open(filename) + if err != nil { + return nil, err + } + defer file.Close() + + buffer := make([]byte, size) + n, err := file.Read(buffer) + if err != nil && err != io.EOF { + return nil, err + } + + // slice the buffer to the actual size + return buffer[:n], nil +} + // ReplacementFunc is a function that is called when a // replacement is being performed. It receives the // variable (i.e. placeholder name) and the value that @@ -363,3 +438,5 @@ var nowFunc = time.Now const ReplacerCtxKey CtxKey = "replacer" const phOpen, phClose, phEscape = '{', '}', '\\' + +const filePrefix = "file." |