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Diffstat (limited to 'app/util.go')
-rwxr-xr-xapp/util.go127
1 files changed, 95 insertions, 32 deletions
diff --git a/app/util.go b/app/util.go
index 1eecc13..8f0cba4 100755
--- a/app/util.go
+++ b/app/util.go
@@ -1,7 +1,9 @@
package app
import (
+ "context"
"encoding/json"
+ "fmt"
"io"
"net/http"
"net/url"
@@ -17,7 +19,12 @@ import (
)
/* INTERNAL */
-var wr = io.WriteString
+
+// wr writes s to w. A write error here means the client went away mid-response,
+// which a handler cannot act on, so it is deliberately discarded.
+func wr(w io.Writer, s string) {
+ _, _ = io.WriteString(w, s)
+}
func exit(msg string, code int) {
println(msg)
@@ -34,15 +41,22 @@ func tryWithExitStatus(err error, code int) {
}
}
+// restore swallows a panic in the calling goroutine so that one bad parse cannot
+// take the whole process down. The panic is logged rather than dropped silently.
func restore() {
if r := recover(); r != nil {
- recover()
+ println("recovered from panic:", fmt.Sprint(r))
}
}
var instances []byte
+
+// About is the instance list and settings shown in the frontend, refreshed by
+// RefreshInstances.
var About instanceAbout
+// RefreshInstances re-fetches the published instance list every hour, forever.
+// Run it in its own goroutine; fetch failures are logged and retried next cycle.
func RefreshInstances() {
for {
func() {
@@ -54,11 +68,11 @@ func RefreshInstances() {
}
}
-// some crap for frontend
+// instanceAbout is the instance metadata exposed to the frontend and the API.
type instanceAbout struct {
- Proxy bool
- Nsfw bool
- Instances []settings
+ Proxy bool `json:"proxy"`
+ Nsfw bool `json:"nsfw"`
+ Instances []settings `json:"instances"`
}
type skunkyart struct {
@@ -118,6 +132,8 @@ type skunkyart struct {
}
}
+// ExecuteTemplate renders the named template from dir with data, responding 500
+// if the template cannot be parsed.
func (s skunkyart) ExecuteTemplate(file, dir string, data any) {
var buf strings.Builder
tmp := template.New(file)
@@ -131,26 +147,30 @@ func (s skunkyart) ExecuteTemplate(file, dir string, data any) {
wr(s.Writer, buf.String())
}
-func UrlBuilder(strs ...string) string {
+// URLBuilder joins strs into an absolute instance URL, prefixing the current
+// Host and configured URI and inserting slashes between path segments but not
+// before query separators.
+func URLBuilder(strs ...string) string {
var str strings.Builder
l := len(strs)
str.WriteString(Host)
str.WriteString(CFG.URI)
for n, x := range strs {
str.WriteString(x)
- if n := n + 1; n < l && len(strs[n]) != 0 && !(strs[n][0] == '?' || strs[n][0] == '&') && !(x[0] == '?' || x[0] == '&') {
+ if n := n + 1; n < l && len(strs[n]) != 0 && (strs[n][0] != '?' && strs[n][0] != '&') && (x[0] != '?' && x[0] != '&') {
str.WriteString("/")
}
}
return str.String()
}
+// Error responds 502 with the error DeviantArt reported upstream.
func (s skunkyart) Error(dAerr devianter.Error) {
s.Writer.WriteHeader(502)
var msg strings.Builder
msg.WriteString(`<html><link rel="stylesheet" href="`)
- msg.WriteString(UrlBuilder("stylesheet"))
+ msg.WriteString(URLBuilder("stylesheet"))
msg.WriteString(`" /><h3>DeviantArt error — '`)
msg.WriteString(dAerr.Error)
msg.WriteString("'</h3></html>")
@@ -158,12 +178,18 @@ func (s skunkyart) Error(dAerr devianter.Error) {
wr(s.Writer, msg.String())
}
+// ReturnHTTPError responds with a styled error page for the given status.
func (s skunkyart) ReturnHTTPError(status int) {
+ // A failed upstream fetch reports status 0, and WriteHeader panics on any
+ // code outside 1xx-5xx. Treat anything unusable as a gateway failure.
+ if status < 100 || status > 599 {
+ status = http.StatusBadGateway
+ }
s.Writer.WriteHeader(status)
var msg strings.Builder
msg.WriteString(`<html><link rel="stylesheet" href="`)
- msg.WriteString(UrlBuilder("stylesheet"))
+ msg.WriteString(URLBuilder("stylesheet"))
msg.WriteString(`" /><h1>`)
msg.WriteString(strconv.Itoa(status))
msg.WriteString(" - ")
@@ -173,6 +199,7 @@ func (s skunkyart) ReturnHTTPError(status int) {
wr(s.Writer, msg.String())
}
+// SetFilename sets the Content-Disposition filename for the response.
func (s skunkyart) SetFilename(name string) {
var filename strings.Builder
filename.WriteString(`filename="`)
@@ -181,29 +208,50 @@ func (s skunkyart) SetFilename(name string) {
s.Writer.Header().Add("Content-Disposition", filename.String())
}
+// Downloaded is the result of a Download. A Status of 0 means the request never
+// completed, in which case Body and Headers are empty.
type Downloaded struct {
Headers http.Header
Status int
Body []byte
}
+// Download fetches urlString with the configured User-Agent, routing through
+// download-proxy when one is set. Every failure path returns the zero
+// Downloaded, so callers must check Status before trusting Body or Headers.
func Download(urlString string) (d Downloaded) {
cli := &http.Client{}
if CFG.DownloadProxy != "" {
- u, e := url.Parse(CFG.DownloadProxy)
- try(e)
- cli.Transport = &http.Transport{Proxy: http.ProxyURL(u)}
+ u, err := url.Parse(CFG.DownloadProxy)
+ if err != nil {
+ try(err)
+ return
+ }
+ cli.Transport = ProxiedTransport(u)
}
- req, e := http.NewRequest("GET", urlString, nil)
- try(e)
+ ctx, cancel := context.WithTimeout(context.Background(), downloadTimeout)
+ defer cancel()
+
+ req, err := http.NewRequestWithContext(ctx, http.MethodGet, urlString, nil)
+ if err != nil {
+ try(err)
+ return
+ }
req.Header.Set("User-Agent", CFG.UserAgent)
- resp, e := cli.Do(req)
- try(e)
- defer resp.Body.Close()
- b, e := io.ReadAll(resp.Body)
- try(e)
+ resp, err := cli.Do(req)
+ if err != nil {
+ try(err)
+ return
+ }
+ defer func() { try(resp.Body.Close()) }()
+
+ b, err := io.ReadAll(resp.Body)
+ if err != nil {
+ try(err)
+ return
+ }
d.Body = b
d.Status = resp.StatusCode
@@ -212,45 +260,56 @@ func Download(urlString string) (d Downloaded) {
}
/* PARSING HELPERS */
+
+// ParseMedia returns the URL to serve for media: a link back through this
+// instance's media proxy when proxying is on, or DeviantArt's own URL when it is
+// off. An optional thumb width selects a thumbnail instead of the full image.
func ParseMedia(media devianter.Media, thumb ...int) string {
- mediaUrl, filename := devianter.UrlFromMedia(media, thumb...)
- if len(mediaUrl) != 0 && CFG.Proxy {
- mediaUrl = mediaUrl[21:]
- dot := strings.Index(mediaUrl, ".")
+ mediaURL, filename := devianter.UrlFromMedia(media, thumb...)
+ if len(mediaURL) != 0 && CFG.Proxy {
+ mediaURL = mediaURL[21:]
+ dot := strings.Index(mediaURL, ".")
if filename == "" {
filename = "image.gif"
}
- return UrlBuilder("media", "file", mediaUrl[:dot], mediaUrl[dot+11:], "&filename=", filename)
+ return URLBuilder("media", "file", mediaURL[:dot], mediaURL[dot+11:], "&filename=", filename)
} else if !CFG.Proxy {
- return mediaUrl
+ return mediaURL
}
return ""
}
-func ConvertDeviantArtUrlToSkunkyArt(url string) (output string) {
+// ConvertDeviantArtURLToSkunkyArt rewrites a deviantart.com post link into the
+// equivalent link on this instance. It returns an empty string for URLs it does
+// not handle, including sta.sh links.
+func ConvertDeviantArtURLToSkunkyArt(url string) (output string) {
if len(url) > 32 && url[27:32] != "stash" {
url = url[27:]
firstshash := strings.Index(url, "/")
lastshash := firstshash + strings.Index(url[firstshash+1:], "/")
if lastshash != -1 {
- output = UrlBuilder("post", url[:firstshash], url[lastshash+2:])
+ output = URLBuilder("post", url[:firstshash], url[lastshash+2:])
}
}
return
}
+// BuildUserPlate renders the small avatar-and-username block linking to a user's
+// about page.
func BuildUserPlate(name string) string {
var htm strings.Builder
htm.WriteString(`<div class="user-plate"><img src="`)
- htm.WriteString(UrlBuilder("media", "emojitar", name, "?type=a"))
+ htm.WriteString(URLBuilder("media", "emojitar", name, "?type=a"))
htm.WriteString(`"><a href="`)
- htm.WriteString(UrlBuilder("group_user", "?type=about&q=", name))
+ htm.WriteString(URLBuilder("group_user", "?type=about&q=", name))
htm.WriteString(`">`)
htm.WriteString(name)
htm.WriteString(`</a></div>`)
return htm.String()
}
+// GetValueOfTag returns the text of the tokenizer's next token, or an empty
+// string if that token is not text.
func GetValueOfTag(t *html.Tokenizer) string {
for tt := t.Next(); ; {
if tt == html.TextToken {
@@ -261,13 +320,17 @@ func GetValueOfTag(t *html.Tokenizer) string {
}
}
-// page navigation
+// DeviationList describes the pagination state of a list of artworks: how many
+// pages exist, and whether another page follows the current one.
type DeviationList struct {
Pages int
More bool
}
-// FIXME: on some artworks the first page can make the navigation panel disappear entirely.
+// NavBase renders the page navigation bar for a list.
+//
+// FIXME: on some artworks the first page can make the navigation panel disappear
+// entirely.
func (s skunkyart) NavBase(c DeviationList) string {
var list strings.Builder
generated by cgit v1.2.3 (git 2.39.1) at 2026-08-04 10:12:29 +0000