Luke Granger-Brown
ad67e1025a
It's neatly partitionable away from the rest of the logic, so it's easier to put it in a separate file.
124 lines
3 KiB
Go
124 lines
3 KiB
Go
// SPDX-FileCopyrightText: 2021 Luke Granger-Brown <depot@lukegb.com>
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//
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// SPDX-License-Identifier: Apache-2.0
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package fuphttp
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import (
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"context"
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"fmt"
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"io"
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"log"
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"net/http"
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"time"
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"github.com/gorilla/mux"
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"gocloud.dev/blob"
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"gocloud.dev/gcerrors"
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)
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func (a *Application) rawDownload(rw http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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vars := mux.Vars(r)
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filename := vars["filename"]
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meta, err := metadata(ctx, a.storageBackend, filename)
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switch errorCode(err) {
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case gcerrors.NotFound:
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a.notFound(rw, r)
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return
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default:
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log.Printf("rawDownload(%q) metadata: %v", filename, err)
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a.internalError(rw, r)
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return
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case gcerrors.OK:
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// OK
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}
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// Do things with attributes?
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if a.redirectToBlobstore {
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redirectExpiry := a.redirectExpiry
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if !meta.ExpiresAt.IsZero() {
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// Cap the redirect lifetime to the remaining lifetime of the object.
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remainingLifetime := meta.ExpiresAt.Sub(time.Now())
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if remainingLifetime < redirectExpiry {
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redirectExpiry = remainingLifetime
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}
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}
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u, err := a.storageBackend.SignedURL(ctx, filename, &blob.SignedURLOptions{
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Expiry: redirectExpiry,
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})
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switch errorCode(err) {
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case gcerrors.NotFound:
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// This is unlikely to get returned.
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a.notFound(rw, r)
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return
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case gcerrors.OK:
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http.Redirect(rw, r, u, http.StatusFound)
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return
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case gcerrors.Unimplemented:
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// Fall back to serving directly.
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default:
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log.Printf("rawDownload(%q) SignedURL (continuing with fallback): %v", filename, err)
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}
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}
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// Perform direct serving.
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a.rawDownloadDirect(ctx, rw, r, filename, meta)
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}
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func (a *Application) rawDownloadDirect(ctx context.Context, rw http.ResponseWriter, r *http.Request, filename string, meta *Metadata) {
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// TODO(lukegb): Range header and conditionals?.
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rdr, err := a.storageBackend.NewReader(ctx, filename, nil)
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switch errorCode(err) {
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case gcerrors.NotFound:
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a.notFound(rw, r)
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return
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default:
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a.internalError(rw, r)
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return
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case gcerrors.OK:
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// OK
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}
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defer rdr.Close()
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attrs := meta.Attributes
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if v := attrs.CacheControl; v != "" {
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rw.Header().Set("Cache-Control", v)
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}
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if v := attrs.ContentDisposition; v != "" {
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rw.Header().Set("Content-Disposition", v)
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}
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if v := attrs.ContentEncoding; v != "" {
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rw.Header().Set("Content-Encoding", v)
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}
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if v := attrs.ContentLanguage; v != "" {
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rw.Header().Set("Content-Language", v)
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}
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if v := attrs.ContentType; v != "" {
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rw.Header().Set("Content-Type", v)
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}
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if v := attrs.ETag; v != "" {
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rw.Header().Set("ETag", v)
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}
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// If we're serving from local disk, use http.ServeContent, using this somewhat opaque method.
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var ior io.Reader
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if rdr.As(&ior) {
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if iors, ok := ior.(io.ReadSeeker); ok {
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http.ServeContent(rw, r, filename, attrs.ModTime, iors)
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return
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}
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}
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if v := attrs.ModTime; !v.IsZero() {
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rw.Header().Set("Last-Modified", v.UTC().Format(http.TimeFormat))
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}
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if v := attrs.Size; v != 0 {
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rw.Header().Set("Content-Length", fmt.Sprintf("%d", v))
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}
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if _, err := io.Copy(rw, rdr); err != nil {
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log.Printf("rawDownloadDirect(%q) copy: %v", filename, err)
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}
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}
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