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Merge pull request #4 from breml/escape-logstash-strings
Add escape/unescape for Logstash strings
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,69 @@ | ||
| package astutil | ||
|
|
||
| import ( | ||
| "regexp" | ||
| ) | ||
|
|
||
| var unescapeRe = regexp.MustCompile(`\\.`) | ||
|
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| // Unescape converts an input containing escape sequences as understood by | ||
| // Logstash (https://www.elastic.co/guide/en/logstash/current/configuration-file-structure.html#_escape_sequences) | ||
| // to an unescaped string. | ||
| // | ||
| // Unescaped character sequences: | ||
| // | ||
| // \r : carriage return (ASCII 13) | ||
| // \n : new line (ASCII 10) | ||
| // \t : tab (ASCII 9) | ||
| // \\ : backslash (ASCII 92) | ||
| // \" : double quote (ASCII 34) | ||
| // \' : single quote (ASCII 39) | ||
| // | ||
| // Based on: | ||
| // https://github.com/elastic/logstash/blob/e9c9865f4066b54048f8d708612a72d25e2fe5d9/logstash-core/lib/logstash/config/string_escape.rb | ||
| func Unescape(value string) string { | ||
| return unescapeRe.ReplaceAllStringFunc(value, func(s string) string { | ||
| switch s[1] { | ||
| case '"', '\'', '\\': | ||
| return string(s[1]) | ||
| case 'n': | ||
| return "\n" | ||
| case 'r': | ||
| return "\r" | ||
| case 't': | ||
| return "\t" | ||
| default: | ||
| return s | ||
| } | ||
| }) | ||
| } | ||
|
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| var escapeRe = regexp.MustCompile(`(?s:.)`) | ||
|
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| // Escape converts an input to an escaped representation as understood by | ||
| // Logstash (https://www.elastic.co/guide/en/logstash/current/configuration-file-structure.html#_escape_sequences). | ||
| // | ||
| // Escaped characters: | ||
| // | ||
| // \r : carriage return (ASCII 13) | ||
| // \n : new line (ASCII 10) | ||
| // \t : tab (ASCII 9) | ||
| // \ : backslash (ASCII 92) | ||
| // " : double quote (ASCII 34) | ||
| // ' : single quote (ASCII 39) | ||
| func Escape(value string) string { | ||
| return escapeRe.ReplaceAllStringFunc(value, func(s string) string { | ||
| switch s { | ||
| case `"`, `'`, `\`: | ||
| return `\` + s | ||
| case "\n": | ||
| return `\n` | ||
| case "\r": | ||
| return `\r` | ||
| case "\t": | ||
| return `\t` | ||
| default: | ||
| return s | ||
| } | ||
| }) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,81 @@ | ||
| package astutil_test | ||
|
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| import ( | ||
| "testing" | ||
|
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| "github.com/breml/logstash-config/ast/astutil" | ||
| ) | ||
|
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| var tt = []struct { | ||
| name string | ||
| escaped string | ||
| unescaped string | ||
| }{ | ||
| { | ||
| name: "carriage return (ASCII 13)", | ||
| escaped: `\r`, | ||
| unescaped: "\r", | ||
| }, | ||
| { | ||
| name: "new line (ASCII 10)", | ||
| escaped: `\n`, | ||
| unescaped: "\n", | ||
| }, | ||
| { | ||
| name: "tab (ASCII 9)", | ||
| escaped: `\t`, | ||
| unescaped: "\t", | ||
| }, | ||
| { | ||
| name: "backslash (ASCII 92)", | ||
| escaped: `\\`, | ||
| unescaped: `\`, | ||
| }, | ||
| { | ||
| name: "double quote (ASCII 34)", | ||
| escaped: `\"`, | ||
| unescaped: `"`, | ||
| }, | ||
| { | ||
| name: "single quote (ASCII 39)", | ||
| escaped: `\'`, | ||
| unescaped: `'`, | ||
| }, | ||
| { | ||
| name: "value containing all special characters", | ||
| escaped: `foo\r\n\t\\\"\'bar`, | ||
| unescaped: "foo\r\n\t\\\"'bar", | ||
| }, | ||
| } | ||
|
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| func TestEscape(t *testing.T) { | ||
| for _, tc := range tt { | ||
| t.Run(tc.name, func(t *testing.T) { | ||
| got := astutil.Escape(tc.unescaped) | ||
| if tc.escaped != got { | ||
| t.Errorf("Escape(%q) != %q, got: %q", tc.unescaped, tc.escaped, got) | ||
| } | ||
| }) | ||
| } | ||
| } | ||
|
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| func TestUnescape(t *testing.T) { | ||
| tt := append(tt, struct { | ||
| name string | ||
| escaped string | ||
| unescaped string | ||
| }{ | ||
| name: "not valid escape", | ||
| escaped: `\x`, | ||
| unescaped: "\\x", | ||
| }) | ||
|
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| for _, tc := range tt { | ||
| t.Run(tc.name, func(t *testing.T) { | ||
| got := astutil.Unescape(tc.escaped) | ||
| if tc.unescaped != got { | ||
| t.Errorf("Unescape(%q) != %q, got: %q", tc.escaped, tc.unescaped, got) | ||
| } | ||
| }) | ||
| } | ||
| } |
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