hugo/tpl/data/data.go

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// Copyright 2017 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package data provides template functions for working with external data
// sources.
package data
import (
"bytes"
"encoding/csv"
"encoding/json"
"errors"
"net/http"
"strings"
"github.com/gohugoio/hugo/cache/filecache"
"github.com/gohugoio/hugo/deps"
_errors "github.com/pkg/errors"
)
// New returns a new instance of the data-namespaced template functions.
func New(deps *deps.Deps) *Namespace {
return &Namespace{
deps: deps,
cacheGetCSV: deps.FileCaches.GetCSVCache(),
cacheGetJSON: deps.FileCaches.GetJSONCache(),
client: http.DefaultClient,
}
}
// Namespace provides template functions for the "data" namespace.
type Namespace struct {
deps *deps.Deps
cacheGetJSON *filecache.Cache
cacheGetCSV *filecache.Cache
client *http.Client
}
// GetCSV expects a data separator and one or n-parts of a URL to a resource which
// can either be a local or a remote one.
// The data separator can be a comma, semi-colon, pipe, etc, but only one character.
// If you provide multiple parts for the URL they will be joined together to the final URL.
// GetCSV returns nil or a slice slice to use in a short code.
func (ns *Namespace) GetCSV(sep string, urlParts ...string) (d [][]string, err error) {
url := strings.Join(urlParts, "")
cache := ns.cacheGetCSV
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unmarshal := func(b []byte) (bool, error) {
if !bytes.Contains(b, []byte(sep)) {
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return false, _errors.Errorf("cannot find separator %s in CSV for %s", sep, url)
}
if d, err = parseCSV(b, sep); err != nil {
err = _errors.Wrapf(err, "failed to parse CSV file %s", url)
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return true, err
}
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return false, nil
}
var req *http.Request
req, err = http.NewRequest("GET", url, nil)
if err != nil {
return nil, _errors.Wrapf(err, "failed to create request for getCSV for resource %s", url)
}
req.Header.Add("Accept", "text/csv")
req.Header.Add("Accept", "text/plain")
err = ns.getResource(cache, unmarshal, req)
if err != nil {
ns.deps.Log.ERROR.Printf("Failed to get CSV resource %q: %s", url, err)
return nil, nil
}
return
}
// GetJSON expects one or n-parts of a URL to a resource which can either be a local or a remote one.
// If you provide multiple parts they will be joined together to the final URL.
// GetJSON returns nil or parsed JSON to use in a short code.
func (ns *Namespace) GetJSON(urlParts ...string) (interface{}, error) {
var v interface{}
url := strings.Join(urlParts, "")
cache := ns.cacheGetJSON
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, _errors.Wrapf(err, "Failed to create request for getJSON resource %s", url)
}
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unmarshal := func(b []byte) (bool, error) {
err := json.Unmarshal(b, &v)
if err != nil {
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return true, err
}
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return false, nil
}
req.Header.Add("Accept", "application/json")
err = ns.getResource(cache, unmarshal, req)
if err != nil {
ns.deps.Log.ERROR.Printf("Failed to get JSON resource %q: %s", url, err)
return nil, nil
}
return v, nil
}
// parseCSV parses bytes of CSV data into a slice slice string or an error
func parseCSV(c []byte, sep string) ([][]string, error) {
if len(sep) != 1 {
return nil, errors.New("Incorrect length of CSV separator: " + sep)
}
b := bytes.NewReader(c)
r := csv.NewReader(b)
rSep := []rune(sep)
r.Comma = rSep[0]
r.FieldsPerRecord = 0
return r.ReadAll()
}