Add url extraction code

pkg/aggregation/urlextraction.go

@@ -0,0 +1,71 @@
+package aggregation
+
+/*
+Regular expression for extracting URLs from https://github.com/mvdan/xurls
+
+Copyright (c) 2015, Daniel Martí. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+import (
+	"net/url"
+	"regexp"
+)
+
+const allowedUcsChar = "¡-ᙿᚁ-\u1fff\u200b-‧\u202a-\u202e‰-⁞\u2060-\u2fff、-\ud7ff豈-﷏ﷰ-\uffef𐀀-\U0001fffd𠀀-\U0002fffd𰀀-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd"
+const allowedUcsCharMinusPunctuation = "¢-¦¨-µ¸-¾À-ͽͿ-ΆΈ-ՙՠ-ֈ֊-ֿׁ-ׂׄ-ׇׅ-ײ\u05f5-؈؋؎-ؚ\u061cؠ-٩ٮ-ۓە-ۿ\u070e-߶ߺ-\u082f\u083f-\u085d\u085f-ॣ०-९ॱ-ৼ৾-ੵ\u0a77-૯૱-\u0c76౸-ಃಅ-ෳ\u0df5-๎๐-๙\u0e5c-༃༓༕-྄྆-࿏࿕-࿘\u0fdb-၉ၐ-ჺჼ-፟፩-᙭ᙯ-ᙿᚁ-ᛪᛮ-᜴\u1737-៓ៗ៛-\u17ff᠆᠋-\u1943᥆-\u1a1dᨠ-\u1a9fᪧ\u1aae-᭙᭡-᭼\u1b7f-\u1bfbᰀ-\u1c3a᱀-ᱽᲀ-Ჿ\u1cc8-᳔᳒-\u1fff\u200b-―‘-‟\u202a-\u202e‹-›‿-⁀⁄-⁆⁒⁔\u2060-\u2cf8⳽ⴀ-ⵯ\u2d71-ⷿ⸂-⸅⸉-⸊⸌-⸍⸗⸚⸜-⸝⸠-⸩ⸯ⸺-⸻⹀⹂⹐-⹑⹕-\u2fff〄-〼〾-ヺー-ꓽꔀ-ꘌꘐ-꙲ꙴ-꙽ꙿ-꛱\ua6f8-ꡳ\ua878-\ua8cd꣐-ꣷꣻꣽ-꤭ꤰ-\ua95eꥠ-꧀\ua9ce-\ua9ddꧠ-\uaa5bꩠ-ꫝꫠ-ꫯꫲ-ꯪ꯬-\ud7ff豈-﷏ﷰ-️︗-︘\ufe1a-︯︱-﹄﹇-﹈﹍-﹏\ufe53﹘-﹞﹢-\ufe67﹩\ufe6c-\uff00＄（-）＋－０-９＜-＞Ａ-［］-｠｢-｣ｦ-\uffef𐀀-\U000100ff\U00010103-\U0001039e𐎠-𐏏𐏑-\U0001056e𐕰-\U00010856𐡘-\U0001091e𐤠-\U0001093e\U00010940-\U00010a4f\U00010a59-𐩾𐪀-𐫯\U00010af7-\U00010b38𐭀-\U00010b98\U00010b9d-𐽔\U00010f5a-𐾅\U00010f8a-𑁆\U0001104e-𑂺\U000110bd𑃂-𑄿𑅄-𑅳𑅶-𑇄𑇉-𑇌𑇎-𑇚𑇜\U000111e0-𑈷𑈾-𑊨\U000112aa-𑑊𑑐-𑑙\U0001145c𑑞-𑓅𑓇-𑗀𑗘-𑙀𑙄-\U0001165f\U0001166d-𑚸\U000116ba-𑜻𑜿-𑠺\U0001183c-𑥃\U00011947-𑧡𑧣-𑨾𑩇-𑪙𑪝\U00011aa3-\U00011aff\U00011b0a-𑱀\U00011c46-\U00011c6f𑱲-𑻶\U00011ef9-𑽂𑽐-\U00011ffe𒀀-\U0001246f\U00012475-𒿰\U00012ff3-\U00016a6d𖩰-𖫴\U00016af6-𖬶𖬼-𖭃𖭅-𖺖\U00016e9b-𖿡𖿣-𛲞\U0001bca0-𝪆\U0001da8c-\U0001e95d\U0001e960-\U0001fffd𠀀-\U0002fffd𰀀-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd"
+
+const (
+	unreservedChar      = `a-zA-Z0-9\-._~`
+	endUnreservedChar   = `a-zA-Z0-9\-_~`
+	midSubDelimChar     = `!$&'*+,;=`
+	endSubDelimChar     = `$&+=`
+	midIPathSegmentChar = unreservedChar + `%` + midSubDelimChar + `:@` + allowedUcsChar
+	endIPathSegmentChar = endUnreservedChar + `%` + endSubDelimChar + allowedUcsCharMinusPunctuation
+	iPrivateChar        = `\x{E000}-\x{F8FF}\x{F0000}-\x{FFFFD}\x{100000}-\x{10FFFD}`
+	midIChar            = `/?#\\` + midIPathSegmentChar + iPrivateChar
+	endIChar            = `/#` + endIPathSegmentChar + iPrivateChar
+	wellParen           = `\((?:[` + midIChar + `]|\([` + midIChar + `]*\))*\)`
+	wellBracket         = `\[(?:[` + midIChar + `]|\[[` + midIChar + `]*\])*\]`
+	wellBrace           = `\{(?:[` + midIChar + `]|\{[` + midIChar + `]*\})*\}`
+	wellAll             = wellParen + `|` + wellBracket + `|` + wellBrace
+	pathCont            = `(?:[` + midIChar + `]*(?:` + wellAll + `|[` + endIChar + `]))+`
+	schemes             = `(?:(?i)(?:http|https)://)`
+)
+
+func extractUrls(text string) []string {
+	re := regexp.MustCompile(schemes + pathCont)
+	re.Longest()
+
+	var urls []string
+	for _, match := range re.FindAllString(text, -1) {
+		if _, err := url.Parse(match); err == nil {
+			urls = append(urls, match)
+		}
+	}
+	return urls
+}

pkg/aggregation/urlextraction_test.go

@@ -0,0 +1,37 @@
+package aggregation
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestExtractUrls(t *testing.T) {
+	tests := []struct {
+		name string
+		text string
+		want []string
+	}{
+		{
+			name: "single",
+			text: "foo http://localhost bar",
+			want: []string{"http://localhost"},
+		},
+		{
+			name: "multiple",
+			text: "foo http://localhost https://www.example.com bar",
+			want: []string{"http://localhost", "https://www.example.com"},
+		},
+		{
+			name: "complex",
+			text: "foo https://www.example.com/x/1234?foo=bar bar",
+			want: []string{"https://www.example.com/x/1234?foo=bar"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := extractUrls(tt.text); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("extractUrls() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}