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chore: gateway_handler.go
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Extract functions from getOrHeadHandler to improve readability and prepare for later refactorings
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Justin Johnson committed Apr 12, 2022
1 parent ca4a3ed commit ec10aa3
Showing 1 changed file with 108 additions and 63 deletions.
171 changes: 108 additions & 63 deletions core/corehttp/gateway_handler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ import (
prometheus "github.com/prometheus/client_golang/prometheus"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/trace"
"go.uber.org/zap"
)

const (
Expand Down Expand Up @@ -324,61 +325,20 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
logger := log.With("from", r.RequestURI)
logger.Debug("http request received")

// X-Ipfs-Gateway-Prefix was removed (https://github.com/ipfs/go-ipfs/issues/7702)
// TODO: remove this after go-ipfs 0.13 ships
if prfx := r.Header.Get("X-Ipfs-Gateway-Prefix"); prfx != "" {
err := fmt.Errorf("X-Ipfs-Gateway-Prefix support was removed: https://github.com/ipfs/go-ipfs/issues/7702")
webError(w, "unsupported HTTP header", err, http.StatusBadRequest)
if handledUnsupportedHeaders(w, r) {
return
}

// ?uri query param support for requests produced by web browsers
// via navigator.registerProtocolHandler Web API
// https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocolHandler
// TLDR: redirect /ipfs/?uri=ipfs%3A%2F%2Fcid%3Fquery%3Dval to /ipfs/cid?query=val
if uriParam := r.URL.Query().Get("uri"); uriParam != "" {
u, err := url.Parse(uriParam)
if err != nil {
webError(w, "failed to parse uri query parameter", err, http.StatusBadRequest)
return
}
if u.Scheme != "ipfs" && u.Scheme != "ipns" {
webError(w, "uri query parameter scheme must be ipfs or ipns", err, http.StatusBadRequest)
return
}
path := u.Path
if u.RawQuery != "" { // preserve query if present
path = path + "?" + u.RawQuery
}

redirectURL := gopath.Join("/", u.Scheme, u.Host, path)
logger.Debugw("uri param, redirect", "to", redirectURL, "status", http.StatusMovedPermanently)
http.Redirect(w, r, redirectURL, http.StatusMovedPermanently)
if handledProtocolHandlerRedirect(w, r, logger) {
return
}

// Service Worker registration request
if r.Header.Get("Service-Worker") == "script" {
// Disallow Service Worker registration on namespace roots
// https://github.com/ipfs/go-ipfs/issues/4025
matched, _ := regexp.MatchString(`^/ip[fn]s/[^/]+$`, r.URL.Path)
if matched {
err := fmt.Errorf("registration is not allowed for this scope")
webError(w, "navigator.serviceWorker", err, http.StatusBadRequest)
return
}
if handledInvalidServiceWorkerRegistration(w, r) {
return
}

contentPath := ipath.New(r.URL.Path)
if pathErr := contentPath.IsValid(); pathErr != nil {
if fixupSuperfluousNamespace(w, r.URL.Path, r.URL.RawQuery) {
// the error was due to redundant namespace, which we were able to fix
// by returning error/redirect page, nothing left to do here
logger.Debugw("redundant namespace; noop")
return
}
// unable to fix path, returning error
webError(w, "invalid ipfs path", pathErr, http.StatusBadRequest)
if handledSuperfluousNamespaces(w, r, contentPath, logger) {
return
}

Expand Down Expand Up @@ -416,26 +376,11 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
return
}

// Update the global metric of the time it takes to read the final root block of the requested resource
// NOTE: for legacy reasons this happens before we go into content-type specific code paths
_, err = i.api.Block().Get(r.Context(), resolvedPath)
if err != nil {
webError(w, "ipfs block get "+resolvedPath.Cid().String(), err, http.StatusInternalServerError)
if i.handledUpdateFirstContentBlockMetrics(w, r, begin, contentPath, resolvedPath) {
return
}
ns := contentPath.Namespace()
timeToGetFirstContentBlock := time.Since(begin).Seconds()
i.unixfsGetMetric.WithLabelValues(ns).Observe(timeToGetFirstContentBlock) // deprecated, use firstContentBlockGetMetric instead
i.firstContentBlockGetMetric.WithLabelValues(ns).Observe(timeToGetFirstContentBlock)

// HTTP Headers
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("X-Ipfs-Path", contentPath.String())

if rootCids, err := i.buildIpfsRootsHeader(contentPath.String(), r); err == nil {
w.Header().Set("X-Ipfs-Roots", rootCids)
} else { // this should never happen, as we resolved the contentPath already
webError(w, "error while resolving X-Ipfs-Roots", err, http.StatusInternalServerError)
if i.handledSetHeaders(w, r, contentPath) {
return
}

Expand Down Expand Up @@ -911,6 +856,77 @@ func debugStr(path string) string {
return q
}

func handledUnsupportedHeaders(w http.ResponseWriter, r *http.Request) bool {
// X-Ipfs-Gateway-Prefix was removed (https://github.com/ipfs/go-ipfs/issues/7702)
// TODO: remove this after go-ipfs 0.13 ships
if prfx := r.Header.Get("X-Ipfs-Gateway-Prefix"); prfx != "" {
err := fmt.Errorf("X-Ipfs-Gateway-Prefix support was removed: https://github.com/ipfs/go-ipfs/issues/7702")
webError(w, "unsupported HTTP header", err, http.StatusBadRequest)
return true
} else {
return false
}
}

// ?uri query param support for requests produced by web browsers
// via navigator.registerProtocolHandler Web API
// https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocolHandler
// TLDR: redirect /ipfs/?uri=ipfs%3A%2F%2Fcid%3Fquery%3Dval to /ipfs/cid?query=val
func handledProtocolHandlerRedirect(w http.ResponseWriter, r *http.Request, logger *zap.SugaredLogger) bool {
if uriParam := r.URL.Query().Get("uri"); uriParam != "" {
u, err := url.Parse(uriParam)
if err != nil {
webError(w, "failed to parse uri query parameter", err, http.StatusBadRequest)
return true
}
if u.Scheme != "ipfs" && u.Scheme != "ipns" {
webError(w, "uri query parameter scheme must be ipfs or ipns", err, http.StatusBadRequest)
return true
}
path := u.Path
if u.RawQuery != "" { // preserve query if present
path = path + "?" + u.RawQuery
}

redirectURL := gopath.Join("/", u.Scheme, u.Host, path)
logger.Debugw("uri param, redirect", "to", redirectURL, "status", http.StatusMovedPermanently)
http.Redirect(w, r, redirectURL, http.StatusMovedPermanently)
return true
}

return false
}

// Disallow Service Worker registration on namespace roots
// https://github.com/ipfs/go-ipfs/issues/4025
func handledInvalidServiceWorkerRegistration(w http.ResponseWriter, r *http.Request) bool {
if r.Header.Get("Service-Worker") == "script" {
matched, _ := regexp.MatchString(`^/ip[fn]s/[^/]+$`, r.URL.Path)
if matched {
err := fmt.Errorf("registration is not allowed for this scope")
webError(w, "navigator.serviceWorker", err, http.StatusBadRequest)
return true
}
}

return false
}

func handledSuperfluousNamespaces(w http.ResponseWriter, r *http.Request, contentPath ipath.Path, logger *zap.SugaredLogger) bool {
if pathErr := contentPath.IsValid(); pathErr != nil {
if fixupSuperfluousNamespace(w, r.URL.Path, r.URL.RawQuery) {
// the error was due to redundant namespace, which we were able to fix
// by returning error/redirect page, nothing left to do here
logger.Debugw("redundant namespace; noop")
return true
}
// unable to fix path, returning error
webError(w, "invalid ipfs path", pathErr, http.StatusBadRequest)
return true
}
return false
}

// Attempt to fix redundant /ipfs/ namespace as long as resulting
// 'intended' path is valid. This is in case gremlins were tickled
// wrong way and user ended up at /ipfs/ipfs/{cid} or /ipfs/ipns/{id}
Expand Down Expand Up @@ -940,3 +956,32 @@ func fixupSuperfluousNamespace(w http.ResponseWriter, urlPath string, urlQuery s
ErrorMsg: fmt.Sprintf("invalid path: %q should be %q", urlPath, intendedPath.String()),
}) == nil
}

func (i *gatewayHandler) handledUpdateFirstContentBlockMetrics(w http.ResponseWriter, r *http.Request, begin time.Time, contentPath ipath.Path, resolvedPath ipath.Resolved) bool {
// Update the global metric of the time it takes to read the final root block of the requested resource
// NOTE: for legacy reasons this happens before we go into content-type specific code paths
_, err := i.api.Block().Get(r.Context(), resolvedPath)
if err != nil {
webError(w, "ipfs block get "+resolvedPath.Cid().String(), err, http.StatusInternalServerError)
return true
}
ns := contentPath.Namespace()
timeToGetFirstContentBlock := time.Since(begin).Seconds()
i.unixfsGetMetric.WithLabelValues(ns).Observe(timeToGetFirstContentBlock) // deprecated, use firstContentBlockGetMetric instead
i.firstContentBlockGetMetric.WithLabelValues(ns).Observe(timeToGetFirstContentBlock)
return false
}

func (i *gatewayHandler) handledSetHeaders(w http.ResponseWriter, r *http.Request, contentPath ipath.Path) bool {
i.addUserHeaders(w) // ok, _now_ write user's headers.
w.Header().Set("X-Ipfs-Path", contentPath.String())

if rootCids, err := i.buildIpfsRootsHeader(contentPath.String(), r); err == nil {
w.Header().Set("X-Ipfs-Roots", rootCids)
} else { // this should never happen, as we resolved the contentPath already
webError(w, "error while resolving X-Ipfs-Roots", err, http.StatusInternalServerError)
return true
}

return false
}

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