pages-server/handler.go

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package main
import (
"bytes"
"fmt"
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"github.com/OrlovEvgeny/go-mcache"
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"github.com/valyala/fasthttp"
"github.com/valyala/fastjson"
"mime"
"path"
"strconv"
"strings"
"time"
)
// handler handles a single HTTP request to the web server.
func handler(ctx *fasthttp.RequestCtx) {
ctx.Response.Header.Set("Server", "Codeberg Pages")
// Force new default from specification (since November 2020) - see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy#strict-origin-when-cross-origin
ctx.Response.Header.Set("Referrer-Policy", "strict-origin-when-cross-origin")
// Enable caching, but require revalidation to reduce confusion
ctx.Response.Header.Set("Cache-Control", "must-revalidate")
// Block all methods not required for static pages
if !ctx.IsGet() && !ctx.IsHead() && !ctx.IsOptions() {
ctx.Response.Header.Set("Allow", "GET, HEAD, OPTIONS")
ctx.Error("Method not allowed", fasthttp.StatusMethodNotAllowed)
return
}
// Block blacklisted paths (like ACME challenges)
for _, blacklistedPath := range BlacklistedPaths {
if bytes.HasPrefix(ctx.Path(), blacklistedPath) {
returnErrorPage(ctx, fasthttp.StatusForbidden)
return
}
}
// Allow CORS for specified domains
if ctx.IsOptions() {
allowCors := false
for _, allowedCorsDomain := range AllowedCorsDomains {
if bytes.Equal(ctx.Request.Host(), allowedCorsDomain) {
allowCors = true
break
}
}
if allowCors {
ctx.Response.Header.Set("Access-Control-Allow-Origin", "*")
ctx.Response.Header.Set("Access-Control-Allow-Methods", "GET, HEAD")
}
ctx.Response.Header.Set("Allow", "GET, HEAD, OPTIONS")
ctx.Response.Header.SetStatusCode(fasthttp.StatusNoContent)
return
}
// Prepare request information to Gitea
var targetOwner, targetRepo, targetBranch, targetPath string
var targetOptions = &upstreamOptions{
ForbiddenMimeTypes: map[string]struct{}{},
TryIndexPages: true,
}
// tryBranch checks if a branch exists and populates the target variables. If canonicalLink is non-empty, it will
// also disallow search indexing and add a Link header to the canonical URL.
var tryBranch = func(repo string, branch string, path []string, canonicalLink string) bool {
if repo == "" {
return false
}
// Check if the branch exists, otherwise treat it as a file path
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branchTimestampResult := getBranchTimestamp(targetOwner, repo, branch)
if branchTimestampResult == nil {
// branch doesn't exist
return false
}
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// Branch exists, use it
targetRepo = repo
targetPath = strings.Trim(strings.Join(path, "/"), "/")
targetBranch = branchTimestampResult.branch
targetOptions.BranchTimestamp = branchTimestampResult.timestamp
if canonicalLink != "" {
// Hide from search machines & add canonical link
ctx.Response.Header.Set("X-Robots-Tag", "noarchive, noindex")
ctx.Response.Header.Set("Link",
strings.NewReplacer("%b", targetBranch, "%p", targetPath).Replace(canonicalLink)+
"; rel=\"canonical\"",
)
}
return true
}
// tryUpstream forwards the target request to the Gitea API, and shows an error page on failure.
var tryUpstream = func() {
// Try to request the file from the Gitea API
if !upstream(ctx, targetOwner, targetRepo, targetBranch, targetPath, targetOptions) {
returnErrorPage(ctx, ctx.Response.StatusCode())
}
}
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if RawDomain != nil && bytes.Equal(ctx.Request.Host(), RawDomain) {
// Serve raw content from RawDomain
targetOptions.TryIndexPages = false
targetOptions.ForbiddenMimeTypes["text/html"] = struct{}{}
targetOptions.DefaultMimeType = "text/plain; charset=utf-8"
pathElements := strings.Split(string(bytes.Trim(ctx.Request.URI().Path(), "/")), "/")
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if len(pathElements) < 2 {
// https://{RawDomain}/{owner}/{repo}[/@{branch}]/{path} is required
ctx.Redirect(RawInfoPage, fasthttp.StatusTemporaryRedirect)
return
}
targetOwner = pathElements[0]
targetRepo = pathElements[1]
// raw.codeberg.page/example/myrepo/@main/index.html
if len(pathElements) > 2 && strings.HasPrefix(pathElements[2], "@") {
if tryBranch(targetRepo, pathElements[2][1:], pathElements[3:],
string(GiteaRoot)+"/"+targetOwner+"/"+targetRepo+"/src/branch/%b/%p",
) {
tryUpstream()
return
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}
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
} else {
tryBranch(targetRepo, "", pathElements[2:],
string(GiteaRoot)+"/"+targetOwner+"/"+targetRepo+"/src/branch/%b/%p",
)
tryUpstream()
return
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}
} else if bytes.HasSuffix(ctx.Request.Host(), MainDomainSuffix) {
// Serve pages from subdomains of MainDomainSuffix
pathElements := strings.Split(string(bytes.Trim(ctx.Request.URI().Path(), "/")), "/")
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targetOwner = string(bytes.TrimSuffix(ctx.Request.Host(), MainDomainSuffix))
targetRepo = pathElements[0]
targetPath = strings.Trim(strings.Join(pathElements[1:], "/"), "/")
// Check if the first directory is a repo with the second directory as a branch
// example.codeberg.page/myrepo/@main/index.html
if len(pathElements) > 1 && strings.HasPrefix(pathElements[1], "@") {
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if targetRepo == "pages" {
// example.codeberg.org/pages/@... redirects to example.codeberg.org/@...
ctx.Redirect("/" + strings.Join(pathElements[1:], "/"), fasthttp.StatusMovedPermanently)
return
}
if tryBranch(pathElements[0], pathElements[1][1:], pathElements[2:],
"/"+pathElements[0]+"/%p",
) {
tryUpstream()
} else {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
}
return
}
// Check if the first directory is a branch for the "pages" repo
// example.codeberg.page/@main/index.html
if strings.HasPrefix(pathElements[0], "@") {
if tryBranch("pages", pathElements[0][1:], pathElements[1:], "/%p") {
tryUpstream()
} else {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
}
return
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}
// Check if the first directory is a repo with a "pages" branch
// example.codeberg.page/myrepo/index.html
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// example.codeberg.page/pages/... is not allowed here.
if pathElements[0] != "pages" && tryBranch(pathElements[0], "pages", pathElements[1:], "") {
tryUpstream()
return
}
// Try to use the "pages" repo on its default branch
// example.codeberg.page/index.html
if tryBranch("pages", "", pathElements, "") {
tryUpstream()
return
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}
// Couldn't find a valid repo/branch
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
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} else {
// Serve pages from external domains
targetOwner, targetRepo, targetBranch, targetPath = getTargetFromDNS(ctx)
if targetOwner == "" {
ctx.Redirect(BrokenDNSPage, fasthttp.StatusTemporaryRedirect)
return
}
}
}
// returnErrorPage sets the response status code and writes NotFoundPage to the response body, with "%status" replaced
// with the provided status code.
func returnErrorPage(ctx *fasthttp.RequestCtx, code int) {
ctx.Response.SetStatusCode(code)
ctx.Response.Header.SetContentType("text/html; charset=utf-8")
ctx.Response.SetBody(bytes.ReplaceAll(NotFoundPage, []byte("%status"), []byte(strconv.Itoa(code)+" "+fasthttp.StatusMessage(code))))
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}
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type branchTimestamp struct {
branch string
timestamp time.Time
}
var branchTimestampCache = mcache.New()
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// getBranchTimestamp finds the default branch (if branch is "") and returns the last modification time of the branch
// (or an empty time.Time if the branch doesn't exist)
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func getBranchTimestamp(owner, repo, branch string) *branchTimestamp {
if result, ok := branchTimestampCache.Get(owner + "/" + repo + "/" + branch); ok {
return result.(*branchTimestamp)
}
result := &branchTimestamp{}
result.branch = branch
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if branch == "" {
var body = make([]byte, 0)
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status, body, err := fasthttp.GetTimeout(body, string(GiteaRoot)+"/api/v1/repos/"+owner+"/"+repo, 10*time.Second)
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if err != nil || status != 200 {
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return nil
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}
branch = fastjson.GetString(body, "default_branch")
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result.branch = branch
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}
var body = make([]byte, 0)
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status, body, err := fasthttp.GetTimeout(body, string(GiteaRoot)+"/api/v1/repos/"+owner+"/"+repo+"/branches/"+branch, 10*time.Second)
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if err != nil || status != 200 {
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return nil
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}
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result.timestamp, _ = time.Parse(time.RFC3339, fastjson.GetString(body, "commit", "timestamp"))
_ = branchTimestampCache.Set(owner + "/" + repo + "/" + branch, result, 15 * time.Second)
return result
}
var upstreamClient = fasthttp.Client{
ReadTimeout: 10 * time.Second,
MaxConnDuration: 60 * time.Second,
MaxConnWaitTimeout: 1000 * time.Millisecond,
MaxConnsPerHost: 1024 * 16, // TODO: adjust bottlenecks for best performance with Gitea!
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}
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// upstream requests a file from the Gitea API at GiteaRoot and writes it to the request context.
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func upstream(ctx *fasthttp.RequestCtx, targetOwner string, targetRepo string, targetBranch string, targetPath string, options *upstreamOptions) (success bool) {
if options.ForbiddenMimeTypes == nil {
options.ForbiddenMimeTypes = map[string]struct{}{}
}
// Check if the branch exists and when it was modified
if options.BranchTimestamp == (time.Time{}) {
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branch := getBranchTimestamp(targetOwner, targetRepo, targetBranch)
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if branch == nil {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return true
}
targetBranch = branch.branch
options.BranchTimestamp = branch.timestamp
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}
if targetOwner == "" || targetRepo == "" || targetBranch == "" {
returnErrorPage(ctx, fasthttp.StatusBadRequest)
return true
}
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// Check if the browser has a cached version
if ifModifiedSince, err := time.Parse(time.RFC1123, string(ctx.Request.Header.Peek("If-Modified-Since"))); err == nil {
if !ifModifiedSince.Before(options.BranchTimestamp) {
ctx.Response.SetStatusCode(fasthttp.StatusNotModified)
return true
}
}
// Make a GET request to the upstream URL
req := fasthttp.AcquireRequest()
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req.SetRequestURI(string(GiteaRoot) + "/api/v1/repos/" + targetOwner + "/" + targetRepo + "/raw/" + targetBranch + "/" + targetPath)
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res := fasthttp.AcquireResponse()
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err := upstreamClient.Do(req, res)
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// Handle errors
if res.StatusCode() == fasthttp.StatusNotFound {
if options.TryIndexPages {
// copy the options struct & try if an index page exists
optionsForIndexPages := *options
optionsForIndexPages.TryIndexPages = false
optionsForIndexPages.AppendTrailingSlash = true
for _, indexPage := range IndexPages {
if upstream(ctx, targetOwner, targetRepo, targetBranch, strings.TrimSuffix(targetPath, "/")+"/"+indexPage, &optionsForIndexPages) {
return true
}
}
}
ctx.Response.SetStatusCode(fasthttp.StatusNotFound)
return false
}
if err != nil || res.StatusCode() != fasthttp.StatusOK {
fmt.Printf("Couldn't fetch contents from \"%s\": %s (status code %d)\n", req.RequestURI(), err, res.StatusCode())
returnErrorPage(ctx, fasthttp.StatusInternalServerError)
return true
}
// Append trailing slash if missing (for index files)
if options.AppendTrailingSlash && !bytes.HasSuffix(ctx.Request.URI().Path(), []byte{'/'}) {
ctx.Redirect(string(ctx.Request.URI().Path())+"/", fasthttp.StatusTemporaryRedirect)
return true
}
// Set the MIME type
mimeType := mime.TypeByExtension(path.Ext(targetPath))
mimeTypeSplit := strings.SplitN(mimeType, ";", 2)
if _, ok := options.ForbiddenMimeTypes[mimeTypeSplit[0]]; ok || mimeType == "" {
if options.DefaultMimeType != "" {
mimeType = options.DefaultMimeType
} else {
mimeType = "application/octet-stream"
}
}
ctx.Response.Header.SetContentType(mimeType)
// Write the response to the original request
ctx.Response.SetStatusCode(fasthttp.StatusOK)
ctx.Response.Header.SetLastModified(options.BranchTimestamp)
err = res.BodyWriteTo(ctx.Response.BodyWriter())
if err != nil {
fmt.Printf("Couldn't write body for \"%s\": %s\n", req.RequestURI(), err)
returnErrorPage(ctx, fasthttp.StatusInternalServerError)
return true
}
return true
}
// upstreamOptions provides various options for the upstream request.
type upstreamOptions struct {
DefaultMimeType string
ForbiddenMimeTypes map[string]struct{}
TryIndexPages bool
AppendTrailingSlash bool
BranchTimestamp time.Time
}