pages-server/server/handler.go
2021-12-05 14:48:45 +01:00

553 lines
20 KiB
Go

package server
import (
"bytes"
"fmt"
"io"
"mime"
"path"
"strconv"
"strings"
"time"
"github.com/OrlovEvgeny/go-mcache"
"github.com/rs/zerolog/log"
"github.com/valyala/fasthttp"
"github.com/valyala/fastjson"
"codeberg.org/codeberg/pages/html"
)
// Handler handles a single HTTP request to the web server.
func Handler(mainDomainSuffix, rawDomain []byte, giteaRoot, rawInfoPage, giteaApiToken string, blacklistedPaths, allowedCorsDomains [][]byte) func(ctx *fasthttp.RequestCtx) {
return func(ctx *fasthttp.RequestCtx) {
log := log.With().Str("Handler", string(ctx.Request.Header.RequestURI())).Logger()
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 browser caching for up to 10 minutes
ctx.Response.Header.Set("Cache-Control", "public, max-age=600")
trimmedHost := TrimHostPort(ctx.Request.Host())
// Add HSTS for RawDomain and MainDomainSuffix
if hsts := GetHSTSHeader(trimmedHost, mainDomainSuffix, rawDomain); hsts != "" {
ctx.Response.Header.Set("Strict-Transport-Security", hsts)
}
// 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(trimmedHost, 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
branchTimestampResult := getBranchTimestamp(targetOwner, repo, branch, giteaRoot, giteaApiToken)
if branchTimestampResult == nil {
// branch doesn't exist
return false
}
// 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() {
// check if a canonical domain exists on a request on MainDomain
if bytes.HasSuffix(trimmedHost, mainDomainSuffix) {
canonicalDomain, _ := checkCanonicalDomain(targetOwner, targetRepo, targetBranch, "", string(mainDomainSuffix), giteaRoot, giteaApiToken)
if !strings.HasSuffix(strings.SplitN(canonicalDomain, "/", 2)[0], string(mainDomainSuffix)) {
canonicalPath := string(ctx.RequestURI())
if targetRepo != "pages" {
canonicalPath = "/" + strings.SplitN(canonicalPath, "/", 3)[2]
}
ctx.Redirect("https://"+canonicalDomain+canonicalPath, fasthttp.StatusTemporaryRedirect)
return
}
}
// Try to request the file from the Gitea API
if !upstream(ctx, targetOwner, targetRepo, targetBranch, targetPath, giteaRoot, giteaApiToken, targetOptions) {
returnErrorPage(ctx, ctx.Response.StatusCode())
}
}
log.Debug().Msg("preparations")
if rawDomain != nil && bytes.Equal(trimmedHost, rawDomain) {
// Serve raw content from RawDomain
log.Debug().Msg("raw domain")
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(), "/")), "/")
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.org/example/myrepo/@main/index.html
if len(pathElements) > 2 && strings.HasPrefix(pathElements[2], "@") {
log.Debug().Msg("raw domain preparations, now trying with specified branch")
if tryBranch(targetRepo, pathElements[2][1:], pathElements[3:],
giteaRoot+"/"+targetOwner+"/"+targetRepo+"/src/branch/%b/%p",
) {
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
return
}
log.Debug().Msg("missing branch")
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
} else {
log.Debug().Msg("raw domain preparations, now trying with default branch")
tryBranch(targetRepo, "", pathElements[2:],
giteaRoot+"/"+targetOwner+"/"+targetRepo+"/src/branch/%b/%p",
)
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
return
}
} else if bytes.HasSuffix(trimmedHost, mainDomainSuffix) {
// Serve pages from subdomains of MainDomainSuffix
log.Debug().Msg("main domain suffix")
pathElements := strings.Split(string(bytes.Trim(ctx.Request.URI().Path(), "/")), "/")
targetOwner = string(bytes.TrimSuffix(trimmedHost, mainDomainSuffix))
targetRepo = pathElements[0]
targetPath = strings.Trim(strings.Join(pathElements[1:], "/"), "/")
if targetOwner == "www" {
// www.codeberg.page redirects to codeberg.page
ctx.Redirect("https://"+string(mainDomainSuffix[1:])+string(ctx.Path()), fasthttp.StatusPermanentRedirect)
return
}
// 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], "@") {
if targetRepo == "pages" {
// example.codeberg.org/pages/@... redirects to example.codeberg.org/@...
ctx.Redirect("/"+strings.Join(pathElements[1:], "/"), fasthttp.StatusTemporaryRedirect)
return
}
log.Debug().Msg("main domain preparations, now trying with specified repo & branch")
if tryBranch(pathElements[0], pathElements[1][1:], pathElements[2:],
"/"+pathElements[0]+"/%p",
) {
log.Debug().Msg("tryBranch, now trying upstream")
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], "@") {
log.Debug().Msg("main domain preparations, now trying with specified branch")
if tryBranch("pages", pathElements[0][1:], pathElements[1:], "/%p") {
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
} else {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
}
return
}
// Check if the first directory is a repo with a "pages" branch
// example.codeberg.page/myrepo/index.html
// example.codeberg.page/pages/... is not allowed here.
log.Debug().Msg("main domain preparations, now trying with specified repo")
if pathElements[0] != "pages" && tryBranch(pathElements[0], "pages", pathElements[1:], "") {
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
return
}
// Try to use the "pages" repo on its default branch
// example.codeberg.page/index.html
log.Debug().Msg("main domain preparations, now trying with default repo/branch")
if tryBranch("pages", "", pathElements, "") {
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
return
}
// Couldn't find a valid repo/branch
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
} else {
trimmedHostStr := string(trimmedHost)
// Serve pages from external domains
targetOwner, targetRepo, targetBranch = getTargetFromDNS(trimmedHostStr, string(mainDomainSuffix))
if targetOwner == "" {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
}
pathElements := strings.Split(string(bytes.Trim(ctx.Request.URI().Path(), "/")), "/")
canonicalLink := ""
if strings.HasPrefix(pathElements[0], "@") {
targetBranch = pathElements[0][1:]
pathElements = pathElements[1:]
canonicalLink = "/%p"
}
// Try to use the given repo on the given branch or the default branch
log.Debug().Msg("custom domain preparations, now trying with details from DNS")
if tryBranch(targetRepo, targetBranch, pathElements, canonicalLink) {
canonicalDomain, valid := checkCanonicalDomain(targetOwner, targetRepo, targetBranch, trimmedHostStr, string(mainDomainSuffix), giteaRoot, giteaApiToken)
if !valid {
returnErrorPage(ctx, fasthttp.StatusMisdirectedRequest)
return
} else if canonicalDomain != trimmedHostStr {
// only redirect if the target is also a codeberg page!
targetOwner, _, _ = getTargetFromDNS(strings.SplitN(canonicalDomain, "/", 2)[0], string(mainDomainSuffix))
if targetOwner != "" {
ctx.Redirect("https://"+canonicalDomain+string(ctx.RequestURI()), fasthttp.StatusTemporaryRedirect)
return
} else {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return
}
}
log.Debug().Msg("tryBranch, now trying upstream")
tryUpstream()
return
} else {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
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")
message := fasthttp.StatusMessage(code)
if code == fasthttp.StatusMisdirectedRequest {
message += " - domain not specified in <code>.domains</code> file"
}
if code == fasthttp.StatusFailedDependency {
message += " - target repo/branch doesn't exist or is private"
}
// TODO: use template engine?
ctx.Response.SetBody(bytes.ReplaceAll(html.NotFoundPage, []byte("%status"), []byte(strconv.Itoa(code)+" "+message)))
}
// DefaultBranchCacheTimeout specifies the timeout for the default branch cache. It can be quite long.
var DefaultBranchCacheTimeout = 15 * time.Minute
// BranchExistanceCacheTimeout specifies the timeout for the branch timestamp & existance cache. It should be shorter
// than FileCacheTimeout, as that gets invalidated if the branch timestamp has changed. That way, repo changes will be
// picked up faster, while still allowing the content to be cached longer if nothing changes.
var BranchExistanceCacheTimeout = 5 * time.Minute
// branchTimestampCache stores branch timestamps for faster cache checking
var branchTimestampCache = mcache.New()
type branchTimestamp struct {
branch string
timestamp time.Time
}
// FileCacheTimeout specifies the timeout for the file content cache - you might want to make this quite long, depending
// on your available memory.
var FileCacheTimeout = 5 * time.Minute
// FileCacheSizeLimit limits the maximum file size that will be cached, and is set to 1 MB by default.
var FileCacheSizeLimit = 1024 * 1024
// fileResponseCache stores responses from the Gitea server
// TODO: make this an MRU cache with a size limit
var fileResponseCache = mcache.New()
type fileResponse struct {
exists bool
mimeType string
body []byte
}
// getBranchTimestamp finds the default branch (if branch is "") and returns the last modification time of the branch
// (or nil if the branch doesn't exist)
func getBranchTimestamp(owner, repo, branch, giteaRoot, giteaApiToken string) *branchTimestamp {
if result, ok := branchTimestampCache.Get(owner + "/" + repo + "/" + branch); ok {
if result == nil {
return nil
}
return result.(*branchTimestamp)
}
result := &branchTimestamp{}
result.branch = branch
if branch == "" {
// Get default branch
var body = make([]byte, 0)
// TODO: use header for API key?
status, body, err := fasthttp.GetTimeout(body, giteaRoot+"/api/v1/repos/"+owner+"/"+repo+"?access_token="+giteaApiToken, 5*time.Second)
if err != nil || status != 200 {
_ = branchTimestampCache.Set(owner+"/"+repo+"/"+branch, nil, DefaultBranchCacheTimeout)
return nil
}
result.branch = fastjson.GetString(body, "default_branch")
}
var body = make([]byte, 0)
status, body, err := fasthttp.GetTimeout(body, giteaRoot+"/api/v1/repos/"+owner+"/"+repo+"/branches/"+branch+"?access_token="+giteaApiToken, 5*time.Second)
if err != nil || status != 200 {
return nil
}
result.timestamp, _ = time.Parse(time.RFC3339, fastjson.GetString(body, "commit", "timestamp"))
_ = branchTimestampCache.Set(owner+"/"+repo+"/"+branch, result, BranchExistanceCacheTimeout)
return result
}
var upstreamClient = fasthttp.Client{
ReadTimeout: 10 * time.Second,
MaxConnDuration: 60 * time.Second,
MaxConnWaitTimeout: 1000 * time.Millisecond,
MaxConnsPerHost: 128 * 16, // TODO: adjust bottlenecks for best performance with Gitea!
}
// upstreamIndexPages lists pages that may be considered as index pages for directories.
var upstreamIndexPages = []string{
"index.html",
}
// upstream requests a file from the Gitea API at GiteaRoot and writes it to the request context.
func upstream(ctx *fasthttp.RequestCtx, targetOwner, targetRepo, targetBranch, targetPath, giteaRoot, giteaApiToken string, options *upstreamOptions) (final bool) {
log := log.With().Strs("upstream", []string{targetOwner, targetRepo, targetBranch, targetPath}).Logger()
if options.ForbiddenMimeTypes == nil {
options.ForbiddenMimeTypes = map[string]struct{}{}
}
// Check if the branch exists and when it was modified
if options.BranchTimestamp == (time.Time{}) {
branch := getBranchTimestamp(targetOwner, targetRepo, targetBranch, giteaRoot, giteaApiToken)
if branch == nil {
returnErrorPage(ctx, fasthttp.StatusFailedDependency)
return true
}
targetBranch = branch.branch
options.BranchTimestamp = branch.timestamp
}
if targetOwner == "" || targetRepo == "" || targetBranch == "" {
returnErrorPage(ctx, fasthttp.StatusBadRequest)
return true
}
// 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
}
}
log.Debug().Msg("preparations")
// Make a GET request to the upstream URL
uri := targetOwner + "/" + targetRepo + "/raw/" + targetBranch + "/" + targetPath
var req *fasthttp.Request
var res *fasthttp.Response
var cachedResponse fileResponse
var err error
if cachedValue, ok := fileResponseCache.Get(uri + "?timestamp=" + strconv.FormatInt(options.BranchTimestamp.Unix(), 10)); ok && len(cachedValue.(fileResponse).body) > 0 {
cachedResponse = cachedValue.(fileResponse)
} else {
req = fasthttp.AcquireRequest()
req.SetRequestURI(giteaRoot + "/api/v1/repos/" + uri + "?access_token=" + giteaApiToken)
res = fasthttp.AcquireResponse()
res.SetBodyStream(&strings.Reader{}, -1)
err = upstreamClient.Do(req, res)
}
log.Debug().Msg("acquisition")
// Handle errors
if (res == nil && !cachedResponse.exists) || (res != nil && 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 upstreamIndexPages {
if upstream(ctx, targetOwner, targetRepo, targetBranch, strings.TrimSuffix(targetPath, "/")+"/"+indexPage, giteaRoot, giteaApiToken, &optionsForIndexPages) {
_ = fileResponseCache.Set(uri+"?timestamp="+strconv.FormatInt(options.BranchTimestamp.Unix(), 10), fileResponse{
exists: false,
}, FileCacheTimeout)
return true
}
}
// compatibility fix for GitHub Pages (/example → /example.html)
optionsForIndexPages.AppendTrailingSlash = false
optionsForIndexPages.RedirectIfExists = string(ctx.Request.URI().Path()) + ".html"
if upstream(ctx, targetOwner, targetRepo, targetBranch, targetPath+".html", giteaRoot, giteaApiToken, &optionsForIndexPages) {
_ = fileResponseCache.Set(uri+"?timestamp="+strconv.FormatInt(options.BranchTimestamp.Unix(), 10), fileResponse{
exists: false,
}, FileCacheTimeout)
return true
}
}
ctx.Response.SetStatusCode(fasthttp.StatusNotFound)
if res != nil {
// Update cache if the request is fresh
_ = fileResponseCache.Set(uri+"?timestamp="+strconv.FormatInt(options.BranchTimestamp.Unix(), 10), fileResponse{
exists: false,
}, FileCacheTimeout)
}
return false
}
if res != nil && (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), and redirect to fix filenames in general
// options.AppendTrailingSlash is only true when looking for index pages
if options.AppendTrailingSlash && !bytes.HasSuffix(ctx.Request.URI().Path(), []byte{'/'}) {
ctx.Redirect(string(ctx.Request.URI().Path())+"/", fasthttp.StatusTemporaryRedirect)
return true
}
if bytes.HasSuffix(ctx.Request.URI().Path(), []byte("/index.html")) {
ctx.Redirect(strings.TrimSuffix(string(ctx.Request.URI().Path()), "index.html"), fasthttp.StatusTemporaryRedirect)
return true
}
if options.RedirectIfExists != "" {
ctx.Redirect(options.RedirectIfExists, fasthttp.StatusTemporaryRedirect)
return true
}
log.Debug().Msg("error handling")
// 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)
// Everything's okay so far
ctx.Response.SetStatusCode(fasthttp.StatusOK)
ctx.Response.Header.SetLastModified(options.BranchTimestamp)
log.Debug().Msg("response preparations")
// Write the response body to the original request
var cacheBodyWriter bytes.Buffer
if res != nil {
if res.Header.ContentLength() > FileCacheSizeLimit {
err = res.BodyWriteTo(ctx.Response.BodyWriter())
} else {
// TODO: cache is half-empty if request is cancelled - does the ctx.Err() below do the trick?
err = res.BodyWriteTo(io.MultiWriter(ctx.Response.BodyWriter(), &cacheBodyWriter))
}
} else {
_, err = ctx.Write(cachedResponse.body)
}
if err != nil {
fmt.Printf("Couldn't write body for \"%s\": %s\n", req.RequestURI(), err)
returnErrorPage(ctx, fasthttp.StatusInternalServerError)
return true
}
log.Debug().Msg("response")
if res != nil && ctx.Err() == nil {
cachedResponse.exists = true
cachedResponse.mimeType = mimeType
cachedResponse.body = cacheBodyWriter.Bytes()
_ = fileResponseCache.Set(uri+"?timestamp="+strconv.FormatInt(options.BranchTimestamp.Unix(), 10), cachedResponse, FileCacheTimeout)
}
return true
}
// upstreamOptions provides various options for the upstream request.
type upstreamOptions struct {
DefaultMimeType string
ForbiddenMimeTypes map[string]struct{}
TryIndexPages bool
AppendTrailingSlash bool
RedirectIfExists string
BranchTimestamp time.Time
}