mirror of https://github.com/perkeep/perkeep.git
137 lines
3.5 KiB
Go
137 lines
3.5 KiB
Go
/*
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Copyright 2011 The Perkeep Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package handlers
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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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"strconv"
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"time"
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"perkeep.org/pkg/blob"
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"perkeep.org/pkg/blobserver"
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)
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const defaultMaxEnumerate = 10000
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const defaultEnumerateSize = 100
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func CreateEnumerateHandler(storage blobserver.BlobEnumerator) http.Handler {
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return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
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handleEnumerateBlobs(rw, req, storage)
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})
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}
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const errMsgMaxWaitSecWithAfter = "Can't use 'maxwaitsec' with 'after'.\n"
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func handleEnumerateBlobs(rw http.ResponseWriter, req *http.Request, storage blobserver.BlobEnumerator) {
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// Potential input parameters
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formValueLimit := req.FormValue("limit")
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formValueMaxWaitSec := req.FormValue("maxwaitsec")
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formValueAfter := req.FormValue("after")
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maxEnumerate := defaultMaxEnumerate
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if config, ok := storage.(blobserver.MaxEnumerateConfig); ok {
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maxEnumerate = config.MaxEnumerate()
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}
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limit := defaultEnumerateSize
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if formValueLimit != "" {
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n, err := strconv.ParseUint(formValueLimit, 10, 32)
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if err != nil || n > uint64(maxEnumerate) {
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limit = maxEnumerate
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} else {
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limit = int(n)
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}
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}
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waitSeconds := 0
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if formValueMaxWaitSec != "" {
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waitSeconds, _ = strconv.Atoi(formValueMaxWaitSec)
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if waitSeconds != 0 && formValueAfter != "" {
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rw.WriteHeader(http.StatusBadRequest)
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fmt.Fprintf(rw, errMsgMaxWaitSecWithAfter)
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return
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}
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switch {
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case waitSeconds < 0:
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waitSeconds = 0
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case waitSeconds > 30:
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// TODO: don't hard-code 30. push this up into a blobserver interface
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// for getting the configuration of the server (ultimately a flag in
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// in the binary)
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waitSeconds = 30
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}
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}
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rw.Header().Set("Content-Type", "text/javascript; charset=utf-8")
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io.WriteString(rw, "{\n \"blobs\": [\n")
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loop := true
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needsComma := false
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deadline := time.Now().Add(time.Duration(waitSeconds) * time.Second)
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after := ""
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for loop && (waitSeconds == 0 || time.Now().After(deadline)) {
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if waitSeconds == 0 {
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loop = false
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}
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blobch := make(chan blob.SizedRef, 100)
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resultch := make(chan error, 1)
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go func() {
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resultch <- storage.EnumerateBlobs(context.TODO(), blobch, formValueAfter, limit)
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}()
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gotBlobs := 0
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for sb := range blobch {
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gotBlobs++
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loop = false
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blobName := sb.Ref.String()
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if needsComma {
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io.WriteString(rw, ",\n")
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}
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fmt.Fprintf(rw, " {\"blobRef\": \"%s\", \"size\": %d}",
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blobName, sb.Size)
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after = blobName
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needsComma = true
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}
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if gotBlobs < limit {
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after = ""
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}
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if err := <-resultch; err != nil {
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log.Printf("Error during enumerate: %v", err)
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fmt.Fprintf(rw, "{{{ SERVER ERROR }}}")
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return
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}
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if loop {
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blobserver.WaitForBlob(storage, deadline, nil)
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}
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}
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io.WriteString(rw, "\n ]")
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if after != "" {
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fmt.Fprintf(rw, ",\n \"continueAfter\": \"%s\"", after)
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}
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const longPollSupported = true
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if longPollSupported {
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io.WriteString(rw, ",\n \"canLongPoll\": true")
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}
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io.WriteString(rw, "\n}\n")
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}
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