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refactor dotenv parser in order to support multi-line variable values…
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,206 @@ | ||
| package godotenv | ||
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| import ( | ||
| "bytes" | ||
| "errors" | ||
| "fmt" | ||
| "strings" | ||
| "unicode" | ||
| ) | ||
|
|
||
| const ( | ||
| charComment = '#' | ||
| prefixSingleQuote = '\'' | ||
| prefixDoubleQuote = '"' | ||
|
|
||
| exportPrefix = "export" | ||
| ) | ||
|
|
||
| func parseBytes(src []byte, out map[string]string) error { | ||
| cutset := src | ||
| for { | ||
| cutset = getStatementStart(cutset) | ||
| if cutset == nil { | ||
| // reached end of file | ||
| break | ||
| } | ||
|
|
||
| key, left, err := locateKeyName(cutset) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| value, left, err := extractVarValue(left, out) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| out[key] = value | ||
| cutset = left | ||
| } | ||
|
|
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| return nil | ||
| } | ||
|
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| // getStatementPosition returns position of statement begin. | ||
| // | ||
| // It skips any comment line or non-whitespace character. | ||
| func getStatementStart(src []byte) []byte { | ||
| pos := indexOfNonSpaceChar(src) | ||
| if pos == -1 { | ||
| return nil | ||
| } | ||
|
|
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| src = src[pos:] | ||
| if src[0] != charComment { | ||
| return src | ||
| } | ||
|
|
||
| // skip comment section | ||
| pos = bytes.IndexFunc(src, isCharFunc('\n')) | ||
| if pos == -1 { | ||
| return nil | ||
| } | ||
|
|
||
| return getStatementStart(src[pos:]) | ||
| } | ||
|
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| // locateKeyName locates and parses key name and returns rest of slice | ||
| func locateKeyName(src []byte) (key string, cutset []byte, err error) { | ||
| // trim "export" and space at beginning | ||
| src = bytes.TrimLeftFunc(bytes.TrimPrefix(src, []byte(exportPrefix)), isSpace) | ||
|
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| // locate key name end and validate it in single loop | ||
| offset := 0 | ||
| loop: | ||
| for i, char := range src { | ||
| rchar := rune(char) | ||
| if isSpace(rchar) { | ||
| continue | ||
| } | ||
|
|
||
| switch char { | ||
| case '=', ':': | ||
| // library also supports yaml-style value declaration | ||
| key = string(src[0:i]) | ||
| offset = i + 1 | ||
| break loop | ||
| case '_': | ||
| default: | ||
| // variable name should match [A-Za-z0-9_] | ||
| if unicode.IsLetter(rchar) || unicode.IsNumber(rchar) { | ||
| continue | ||
| } | ||
|
|
||
| return "", nil, fmt.Errorf( | ||
| `unexpected character %q in variable name near %q`, | ||
| string(char), string(src)) | ||
| } | ||
| } | ||
|
|
||
| if len(src) == 0 { | ||
| return "", nil, errors.New("zero length string") | ||
| } | ||
|
|
||
| // trim whitespace | ||
| key = strings.TrimRightFunc(key, unicode.IsSpace) | ||
| cutset = bytes.TrimLeftFunc(src[offset:], isSpace) | ||
| return key, cutset, nil | ||
| } | ||
|
|
||
| // extractVarValue extracts variable value and returns rest of slice | ||
| func extractVarValue(src []byte, vars map[string]string) (value string, rest []byte, err error) { | ||
| quote, hasPrefix := hasQuotePrefix(src) | ||
| if !hasPrefix { | ||
| // unquoted value - read until whitespace | ||
| end := bytes.IndexFunc(src, unicode.IsSpace) | ||
| if end == -1 { | ||
| return expandVariables(string(src), vars), nil, nil | ||
| } | ||
|
|
||
| return expandVariables(string(src[0:end]), vars), src[end:], nil | ||
| } | ||
|
|
||
| // lookup quoted string terminator | ||
| for i := 1; i < len(src); i++ { | ||
| if char := src[i]; char != quote { | ||
| continue | ||
| } | ||
|
|
||
| // skip escaped quote symbol (\" or \', depends on quote) | ||
| if prevChar := src[i-1]; prevChar == '\\' { | ||
| continue | ||
| } | ||
|
|
||
| // trim quotes | ||
| trimFunc := isCharFunc(rune(quote)) | ||
| value = string(bytes.TrimLeftFunc(bytes.TrimRightFunc(src[0:i], trimFunc), trimFunc)) | ||
| if quote == prefixDoubleQuote { | ||
| // unescape newlines for double quote (this is compat feature) | ||
| // and expand environment variables | ||
| value = expandVariables(expandEscapes(value), vars) | ||
| } | ||
|
|
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| return value, src[i+1:], nil | ||
| } | ||
|
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| // return formatted error if quoted string is not terminated | ||
| valEndIndex := bytes.IndexFunc(src, isCharFunc('\n')) | ||
| if valEndIndex == -1 { | ||
| valEndIndex = len(src) | ||
| } | ||
|
|
||
| return "", nil, fmt.Errorf("unterminated quoted value %s", src[:valEndIndex]) | ||
| } | ||
|
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| func expandEscapes(str string) string { | ||
| out := escapeRegex.ReplaceAllStringFunc(str, func(match string) string { | ||
| c := strings.TrimPrefix(match, `\`) | ||
| switch c { | ||
| case "n": | ||
| return "\n" | ||
| case "r": | ||
| return "\r" | ||
| default: | ||
| return match | ||
| } | ||
| }) | ||
| return unescapeCharsRegex.ReplaceAllString(out, "$1") | ||
| } | ||
|
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| func indexOfNonSpaceChar(src []byte) int { | ||
| return bytes.IndexFunc(src, func(r rune) bool { | ||
| return !unicode.IsSpace(r) | ||
| }) | ||
| } | ||
|
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| // hasQuotePrefix reports whether charset starts with single or double quote and returns quote character | ||
| func hasQuotePrefix(src []byte) (prefix byte, isQuored bool) { | ||
| if len(src) == 0 { | ||
| return 0, false | ||
| } | ||
|
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||
| switch prefix := src[0]; prefix { | ||
| case prefixDoubleQuote, prefixSingleQuote: | ||
| return prefix, true | ||
| default: | ||
| return 0, false | ||
| } | ||
| } | ||
|
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| func isCharFunc(char rune) func(rune) bool { | ||
| return func(v rune) bool { | ||
| return v == char | ||
| } | ||
| } | ||
|
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| // isSpace reports whether the rune is a space character but not line break character | ||
| // | ||
| // this differs from unicode.IsSpace, which also applies line break as space | ||
| func isSpace(r rune) bool { | ||
| switch r { | ||
| case '\t', '\v', '\f', '\r', ' ', 0x85, 0xA0: | ||
| return true | ||
| } | ||
| return false | ||
| } |