Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame^] | 1 | package restful |
| 2 | |
| 3 | // Copyright 2013 Ernest Micklei. All rights reserved. |
| 4 | // Use of this source code is governed by a license |
| 5 | // that can be found in the LICENSE file. |
| 6 | |
| 7 | import ( |
| 8 | "bytes" |
| 9 | "fmt" |
| 10 | "regexp" |
| 11 | "strings" |
| 12 | ) |
| 13 | |
| 14 | // PathExpression holds a compiled path expression (RegExp) needed to match against |
| 15 | // Http request paths and to extract path parameter values. |
| 16 | type pathExpression struct { |
| 17 | LiteralCount int // the number of literal characters (means those not resulting from template variable substitution) |
| 18 | VarNames []string // the names of parameters (enclosed by {}) in the path |
| 19 | VarCount int // the number of named parameters (enclosed by {}) in the path |
| 20 | Matcher *regexp.Regexp |
| 21 | Source string // Path as defined by the RouteBuilder |
| 22 | tokens []string |
| 23 | } |
| 24 | |
| 25 | // NewPathExpression creates a PathExpression from the input URL path. |
| 26 | // Returns an error if the path is invalid. |
| 27 | func newPathExpression(path string) (*pathExpression, error) { |
| 28 | expression, literalCount, varNames, varCount, tokens := templateToRegularExpression(path) |
| 29 | compiled, err := regexp.Compile(expression) |
| 30 | if err != nil { |
| 31 | return nil, err |
| 32 | } |
| 33 | return &pathExpression{literalCount, varNames, varCount, compiled, expression, tokens}, nil |
| 34 | } |
| 35 | |
| 36 | // http://jsr311.java.net/nonav/releases/1.1/spec/spec3.html#x3-370003.7.3 |
| 37 | func templateToRegularExpression(template string) (expression string, literalCount int, varNames []string, varCount int, tokens []string) { |
| 38 | var buffer bytes.Buffer |
| 39 | buffer.WriteString("^") |
| 40 | //tokens = strings.Split(template, "/") |
| 41 | tokens = tokenizePath(template) |
| 42 | for _, each := range tokens { |
| 43 | if each == "" { |
| 44 | continue |
| 45 | } |
| 46 | buffer.WriteString("/") |
| 47 | if strings.HasPrefix(each, "{") { |
| 48 | // check for regular expression in variable |
| 49 | colon := strings.Index(each, ":") |
| 50 | var varName string |
| 51 | if colon != -1 { |
| 52 | // extract expression |
| 53 | varName = strings.TrimSpace(each[1:colon]) |
| 54 | paramExpr := strings.TrimSpace(each[colon+1 : len(each)-1]) |
| 55 | if paramExpr == "*" { // special case |
| 56 | buffer.WriteString("(.*)") |
| 57 | } else { |
| 58 | buffer.WriteString(fmt.Sprintf("(%s)", paramExpr)) // between colon and closing moustache |
| 59 | } |
| 60 | } else { |
| 61 | // plain var |
| 62 | varName = strings.TrimSpace(each[1 : len(each)-1]) |
| 63 | buffer.WriteString("([^/]+?)") |
| 64 | } |
| 65 | varNames = append(varNames, varName) |
| 66 | varCount += 1 |
| 67 | } else { |
| 68 | literalCount += len(each) |
| 69 | encoded := each // TODO URI encode |
| 70 | buffer.WriteString(regexp.QuoteMeta(encoded)) |
| 71 | } |
| 72 | } |
| 73 | return strings.TrimRight(buffer.String(), "/") + "(/.*)?$", literalCount, varNames, varCount, tokens |
| 74 | } |