From 4f71a2a090c1583b2bc2e714234994731e1844e1 Mon Sep 17 00:00:00 2001
From: Jan-Lukas Else <mail@jlelse.de>
Date: Tue, 15 Sep 2020 17:01:53 +0200
Subject: [PATCH] Add method to generate post summaries, extend feeds

---
 config.go                |  2 ++
 example-config.yaml      |  1 +
 feeds.go                 |  9 +++++----
 go.mod                   |  6 ++++--
 go.sum                   | 12 ++++++++----
 postFuncs.go             | 34 ++++++++++++++++++++++++++++++++++
 posts.go                 | 13 +------------
 render.go                |  3 +++
 templates/summary.gohtml |  2 +-
 utils.go                 | 12 ++++++++++++
 10 files changed, 71 insertions(+), 23 deletions(-)
 create mode 100644 postFuncs.go

diff --git a/config.go b/config.go
index 928c0d2..4068e08 100644
--- a/config.go
+++ b/config.go
@@ -16,6 +16,7 @@ type configServer struct {
 	Logging         bool   `mapstructure:"logging"`
 	Port            int    `mapstructure:"port"`
 	Domain          string `mapstructure:"domain"`
+	PublicAddress   string `mapstructure:"publicAddress"`
 	PublicHttps     bool   `mapstructure:"publicHttps"`
 	LetsEncryptMail string `mapstructure:"letsEncryptMail"`
 	LocalHttps      bool   `mapstructure:"localHttps"`
@@ -77,6 +78,7 @@ func initConfig() error {
 	viper.SetDefault("server.logging", false)
 	viper.SetDefault("server.port", 8080)
 	viper.SetDefault("server.domain", "example.com")
+	viper.SetDefault("server.publicAddress", "http://localhost:8080")
 	viper.SetDefault("server.publicHttps", false)
 	viper.SetDefault("server.letsEncryptMail", "mail@example.com")
 	viper.SetDefault("server.localHttps", false)
diff --git a/example-config.yaml b/example-config.yaml
index 3ed9370..a292800 100644
--- a/example-config.yaml
+++ b/example-config.yaml
@@ -2,6 +2,7 @@ server:
   logging: false
   port: 8080
   domain: example.com
+  publicAdress: http://localhost:8080
   publicHttps: false
   letsEncryptMail: mail@example.com
   localHttps: false
diff --git a/feeds.go b/feeds.go
index 0488e98..961cb8b 100644
--- a/feeds.go
+++ b/feeds.go
@@ -3,6 +3,7 @@ package main
 import (
 	"github.com/gorilla/feeds"
 	"net/http"
+	"strings"
 	"time"
 )
 
@@ -15,20 +16,20 @@ const (
 	JSON feedType = "json"
 )
 
-func generateFeed(f feedType, w http.ResponseWriter, posts []*Post, title string, description string) {
+func generateFeed(f feedType, w http.ResponseWriter, r *http.Request, posts []*Post, title string, description string) {
 	now := time.Now()
 	feed := &feeds.Feed{
 		Title:       title,
 		Description: description,
-		Link:        &feeds.Link{},
+		Link:        &feeds.Link{Href: appConfig.Server.PublicAddress + strings.TrimSuffix(r.URL.Path, "."+string(f))},
 		Created:     now,
 	}
 	for _, postItem := range posts {
 		htmlContent, _ := renderMarkdown(postItem.Content)
 		feed.Add(&feeds.Item{
 			Title:       postItem.title(),
-			Link:        &feeds.Link{Href: postItem.Path},
-			Description: string(htmlContent),
+			Link:        &feeds.Link{Href: appConfig.Server.PublicAddress + postItem.Path},
+			Description: postItem.summary(),
 			Id:          postItem.Path,
 			Content:     string(htmlContent),
 		})
diff --git a/go.mod b/go.mod
index f6ce475..7a2ef68 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,8 @@ module git.jlel.se/jlelse/GoBlog
 go 1.15
 
 require (
+	github.com/PuerkitoBio/goquery v1.5.1
+	github.com/andybalholm/cascadia v1.2.0 // indirect
 	github.com/caddyserver/certmagic v0.11.2
 	github.com/cenkalti/backoff/v4 v4.0.2 // indirect
 	github.com/go-acme/lego/v3 v3.9.0 // indirect
@@ -24,7 +26,7 @@ require (
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pelletier/go-toml v1.8.1 // indirect
 	github.com/smartystreets/assertions v1.2.0 // indirect
-	github.com/spf13/afero v1.3.5 // indirect
+	github.com/spf13/afero v1.4.0 // indirect
 	github.com/spf13/cast v1.3.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/viper v1.7.1
@@ -34,7 +36,7 @@ require (
 	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a // indirect
 	golang.org/x/net v0.0.0-20200904194848-62affa334b73 // indirect
 	golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208 // indirect
-	golang.org/x/sys v0.0.0-20200909081042-eff7692f9009 // indirect
+	golang.org/x/sys v0.0.0-20200915084602-288bc346aa39 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	gopkg.in/check.v1 v1.0.0-20200902074654-038fdea0a05b // indirect
 	gopkg.in/ini.v1 v1.61.0 // indirect
diff --git a/go.sum b/go.sum
index c53cfe1..8809070 100644
--- a/go.sum
+++ b/go.sum
@@ -41,6 +41,7 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
 github.com/OpenDNS/vegadns2client v0.0.0-20180418235048-a3fa4a771d87/go.mod h1:iGLljf5n9GjT6kc0HBvyI1nOKnGQbNB66VzSNbK5iks=
+github.com/PuerkitoBio/goquery v1.5.1 h1:PSPBGne8NIUWw+/7vFBV+kG2J/5MOjbzc7154OaKCSE=
 github.com/PuerkitoBio/goquery v1.5.1/go.mod h1:GsLWisAFVj4WgDibEWF4pvYnkVQBpKBKeU+7zCJoLcc=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
@@ -49,7 +50,10 @@ github.com/akamai/AkamaiOPEN-edgegrid-golang v0.9.18/go.mod h1:L+HB2uBoDgi3+r1pJ
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/aliyun/alibaba-cloud-sdk-go v1.61.112/go.mod h1:pUKYbK5JQ+1Dfxk80P0qxGqe5dkxDoabbZS7zOcouyA=
+github.com/andybalholm/cascadia v1.1.0 h1:BuuO6sSfQNFRu1LppgbD25Hr2vLYW25JvxHs5zzsLTo=
 github.com/andybalholm/cascadia v1.1.0/go.mod h1:GsXiBklL0woXo1j/WYWtSYYC4ouU9PqHO0sqidkEA4Y=
+github.com/andybalholm/cascadia v1.2.0 h1:vuRCkM5Ozh/BfmsaTm26kbjm0mIOM3yS5Ek/F5h18aE=
+github.com/andybalholm/cascadia v1.2.0/go.mod h1:YCyR8vOZT9aZ1CHEd8ap0gMVm2aFgxBp0T0eFw1RUQY=
 github.com/apache/thrift v0.12.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da/go.mod h1:Q73ZrmVTwzkszR9V5SSuryQ31EELlFMUz1kKyl939pY=
@@ -388,8 +392,8 @@ github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4k
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/spf13/afero v1.1.2 h1:m8/z1t7/fwjysjQRYbP0RD+bUIF/8tJwPdEZsI83ACI=
 github.com/spf13/afero v1.1.2/go.mod h1:j4pytiNVoe2o6bmDsKpLACNPDBIoEAkihy7loJ1B0CQ=
-github.com/spf13/afero v1.3.5 h1:AWZ/w4lcfxuh52NVL78p9Eh8j6r1mCTEGSRFBJyIHAE=
-github.com/spf13/afero v1.3.5/go.mod h1:Ai8FlHk4v/PARR026UzYexafAt9roJ7LcLMAmO6Z93I=
+github.com/spf13/afero v1.4.0 h1:jsLTaI1zwYO3vjrzHalkVcIHXTNmdQFepW4OI8H3+x8=
+github.com/spf13/afero v1.4.0/go.mod h1:Ai8FlHk4v/PARR026UzYexafAt9roJ7LcLMAmO6Z93I=
 github.com/spf13/cast v1.3.0 h1:oget//CVOEoFewqQxwr0Ej5yjygnqGkvggSE/gB35Q8=
 github.com/spf13/cast v1.3.0/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
 github.com/spf13/cast v1.3.1 h1:nFm6S0SMdyzrzcmThSipiEubIDy8WEXKNZ0UOgiRpng=
@@ -581,8 +585,8 @@ golang.org/x/sys v0.0.0-20200302150141-5c8b2ff67527/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c h1:UIcGWL6/wpCfyGuJnRFJRurA+yj8RrW7Q6x2YMCXt6c=
 golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200909081042-eff7692f9009 h1:W0lCpv29Hv0UaM1LXb9QlBHLNP8UFfcKjblhVCWftOM=
-golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200915084602-288bc346aa39 h1:356XA7ITklAU2//sYkjFeco+dH1bCRD8XCJ9FIEsvo4=
+golang.org/x/sys v0.0.0-20200915084602-288bc346aa39/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
diff --git a/postFuncs.go b/postFuncs.go
new file mode 100644
index 0000000..ae41686
--- /dev/null
+++ b/postFuncs.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"github.com/PuerkitoBio/goquery"
+	"strings"
+)
+
+func (p *Post) firstParameter(parameter string) (result string) {
+	if pp := p.Parameters[parameter]; len(pp) > 0 {
+		result = pp[0]
+	}
+	return
+}
+
+func (p *Post) title() string {
+	return p.firstParameter("title")
+}
+
+func (p *Post) summary() (summary string) {
+	summary = p.firstParameter("summary")
+	if summary != "" {
+		return
+	}
+	summaryDivider := "<!--more-->"
+	rendered, _ := renderMarkdown(p.Content)
+	if strings.Contains(string(rendered), summaryDivider) {
+		doc, _ := goquery.NewDocumentFromReader(strings.NewReader(strings.Split(string(rendered), summaryDivider)[0]))
+		summary = doc.Text()
+		return
+	}
+	doc, _ := goquery.NewDocumentFromReader(strings.NewReader(string(rendered)))
+	summary = firstSentences(doc.Text(), 3)
+	return
+}
diff --git a/posts.go b/posts.go
index cb95b2f..07820a7 100644
--- a/posts.go
+++ b/posts.go
@@ -23,17 +23,6 @@ type Post struct {
 	Parameters map[string][]string `json:"parameters"`
 }
 
-func (p *Post) firstParameter(parameter string) (result string) {
-	if pp := p.Parameters[parameter]; len(pp) > 0 {
-		result = pp[0]
-	}
-	return
-}
-
-func (p *Post) title() string {
-	return p.firstParameter("title")
-}
-
 func servePost(w http.ResponseWriter, r *http.Request) {
 	path := slashTrimmedPath(r)
 	post, err := getPost(r.Context(), path)
@@ -147,7 +136,7 @@ func serveIndex(path string, sec *section, tax *taxonomy, taxonomyValue string,
 		}
 		// Check if feed
 		if ft != NONE {
-			generateFeed(ft, w, posts, title, description)
+			generateFeed(ft, w, r, posts, title, description)
 			return
 		}
 		// Navigation
diff --git a/render.go b/render.go
index fa29756..53c857f 100644
--- a/render.go
+++ b/render.go
@@ -42,6 +42,9 @@ func initRendering() {
 		"title": func(post *Post) string {
 			return post.title()
 		},
+		"summary": func(post *Post) string {
+			return post.summary()
+		},
 		"include": func(templateName string, data interface{}) (template.HTML, error) {
 			buf := new(bytes.Buffer)
 			err := templates[templateName].ExecuteTemplate(buf, templateName, data)
diff --git a/templates/summary.gohtml b/templates/summary.gohtml
index cd290ea..7880bd6 100644
--- a/templates/summary.gohtml
+++ b/templates/summary.gohtml
@@ -1,7 +1,7 @@
 {{ define "summary" }}
   <article>
       {{ with p . "title" }}<h2>{{ . }}</h2>{{ end }}
-    <p>{{ md .Content }}</p>
+    <p>{{ summary . }}</p>
     <a href="{{ .Path }}">View</a>
   </article>
   <hr>
diff --git a/utils.go b/utils.go
index 1a87a64..cd81805 100644
--- a/utils.go
+++ b/utils.go
@@ -26,3 +26,15 @@ func urlize(str string) string {
 	}
 	return newStr
 }
+
+func firstSentences(value string, count int) string {
+	for i := range value {
+		if value[i] == '.' || value[i] == '!' || value[i] == '?' {
+			count -= 1
+			if count == 0 && i < len(value) {
+				return value[0 : i+1]
+			}
+		}
+	}
+	return value
+}