1// Copyright 2018 The Hugo Authors. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14// Package templates contains functions for template processing of Resource objects.
15package templates
16
17import (
18	"github.com/gohugoio/hugo/helpers"
19	"github.com/gohugoio/hugo/resources"
20	"github.com/gohugoio/hugo/resources/internal"
21	"github.com/gohugoio/hugo/resources/resource"
22	"github.com/gohugoio/hugo/tpl"
23	"github.com/pkg/errors"
24)
25
26// Client contains methods to perform template processing of Resource objects.
27type Client struct {
28	rs *resources.Spec
29	t  tpl.TemplatesProvider
30}
31
32// New creates a new Client with the given specification.
33func New(rs *resources.Spec, t tpl.TemplatesProvider) *Client {
34	if rs == nil {
35		panic("must provice a resource Spec")
36	}
37	if t == nil {
38		panic("must provide a template provider")
39	}
40	return &Client{rs: rs, t: t}
41}
42
43type executeAsTemplateTransform struct {
44	rs         *resources.Spec
45	t          tpl.TemplatesProvider
46	targetPath string
47	data       interface{}
48}
49
50func (t *executeAsTemplateTransform) Key() internal.ResourceTransformationKey {
51	return internal.NewResourceTransformationKey("execute-as-template", t.targetPath)
52}
53
54func (t *executeAsTemplateTransform) Transform(ctx *resources.ResourceTransformationCtx) error {
55	tplStr := helpers.ReaderToString(ctx.From)
56	templ, err := t.t.TextTmpl().Parse(ctx.InPath, tplStr)
57	if err != nil {
58		return errors.Wrapf(err, "failed to parse Resource %q as Template:", ctx.InPath)
59	}
60
61	ctx.OutPath = t.targetPath
62
63	return t.t.Tmpl().Execute(templ, ctx.To, t.data)
64}
65
66func (c *Client) ExecuteAsTemplate(res resources.ResourceTransformer, targetPath string, data interface{}) (resource.Resource, error) {
67	return res.Transform(&executeAsTemplateTransform{
68		rs:         c.rs,
69		targetPath: helpers.ToSlashTrimLeading(targetPath),
70		t:          c.t,
71		data:       data,
72	})
73}
74