/
get_rows_handler.go
88 lines (83 loc) · 1.96 KB
/
get_rows_handler.go
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// SPDX-License-Identifier: Apache-2.0
// Copyright © 2021 Wrangle Ltd
package apiserver
import (
"compress/gzip"
"encoding/csv"
"encoding/hex"
"fmt"
"net/http"
"net/url"
"regexp"
"strconv"
"strings"
"github.com/wrgl/core/pkg/api"
"github.com/wrgl/core/pkg/diff"
"github.com/wrgl/core/pkg/objects"
)
var rowsURIPat = regexp.MustCompile(`/tables/([0-9a-f]{32})/rows/`)
func (s *Server) handleGetRows(rw http.ResponseWriter, r *http.Request) {
m := rowsURIPat.FindStringSubmatch(r.URL.Path)
if m == nil {
http.NotFound(rw, r)
return
}
sum, err := hex.DecodeString(m[1])
if err != nil {
panic(err)
}
db := s.getDB(r)
tbl, err := objects.GetTable(db, sum)
if err != nil {
http.NotFound(rw, r)
return
}
values := r.URL.Query()
var offsets []uint32
if v, ok := values["offsets"]; ok {
sl := strings.Split(v[0], ",")
offsets = make([]uint32, len(sl))
for i, s := range sl {
u, err := strconv.Atoi(s)
if err != nil {
http.Error(rw, fmt.Sprintf("invalid offset %q", s), http.StatusBadRequest)
return
}
if u < 0 || u > int(tbl.RowsCount) {
http.Error(rw, fmt.Sprintf("offset out of range %q", s), http.StatusBadRequest)
return
}
offsets[i] = uint32(u)
}
}
if len(offsets) == 0 {
// redirect to blocks endpoint to download everything
url := &url.URL{}
*url = *r.URL
url.Path = fmt.Sprintf("/tables/%x/blocks/", sum)
http.Redirect(rw, r, url.String(), http.StatusTemporaryRedirect)
return
}
buf, err := diff.NewBlockBuffer([]objects.Store{db}, []*objects.Table{tbl})
if err != nil {
panic(err)
}
s.cacheControlImmutable(rw)
rw.Header().Set("Content-Encoding", "gzip")
gzw := gzip.NewWriter(rw)
defer gzw.Close()
rw.Header().Set("Content-Type", api.CTCSV)
w := csv.NewWriter(gzw)
defer w.Flush()
for _, o := range offsets {
blk, row := diff.RowToBlockAndOffset(o)
strs, err := buf.GetRow(0, blk, row)
if err != nil {
panic(err)
}
err = w.Write(strs)
if err != nil {
panic(err)
}
}
}