Add basic "post resource publish support"

Fixes #7146

deps/deps.go

@@ -2,6 +2,7 @@ package deps
 
 import (
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/pkg/errors"
@@ -92,8 +93,9 @@ type Deps struct {
 	// BuildStartListeners will be notified before a build starts.
 	BuildStartListeners *Listeners
 
-	// Atomic flags set during a build.
-	BuildFlags *BuildFlags
+	// Atomic values set during a build.
+	// This is common/global for all sites.
+	BuildState *BuildState
 
 	*globalErrHandler
 }
@@ -236,8 +238,9 @@ func New(cfg DepsCfg) (*Deps, error) {
 	}
 
 	errorHandler := &globalErrHandler{}
+	buildState := &BuildState{}
 
-	resourceSpec, err := resources.NewSpec(ps, fileCaches, logger, errorHandler, cfg.OutputFormats, cfg.MediaTypes)
+	resourceSpec, err := resources.NewSpec(ps, fileCaches, buildState, logger, errorHandler, cfg.OutputFormats, cfg.MediaTypes)
 	if err != nil {
 		return nil, err
 	}
@@ -275,7 +278,7 @@ func New(cfg DepsCfg) (*Deps, error) {
 		Site:                    cfg.Site,
 		FileCaches:              fileCaches,
 		BuildStartListeners:     &Listeners{},
-		BuildFlags:              &BuildFlags{},
+		BuildState:              buildState,
 		Timeout:                 time.Duration(timeoutms) * time.Millisecond,
 		globalErrHandler:        errorHandler,
 	}
@@ -308,7 +311,7 @@ func (d Deps) ForLanguage(cfg DepsCfg, onCreated func(d *Deps) error) (*Deps, er
 	// The resource cache is global so reuse.
 	// TODO(bep) clean up these inits.
 	resourceCache := d.ResourceSpec.ResourceCache
-	d.ResourceSpec, err = resources.NewSpec(d.PathSpec, d.ResourceSpec.FileCaches, d.Log, d.globalErrHandler, cfg.OutputFormats, cfg.MediaTypes)
+	d.ResourceSpec, err = resources.NewSpec(d.PathSpec, d.ResourceSpec.FileCaches, d.BuildState, d.Log, d.globalErrHandler, cfg.OutputFormats, cfg.MediaTypes)
 	if err != nil {
 		return nil, err
 	}
@@ -376,10 +379,15 @@ type DepsCfg struct {
 	Running bool
 }
 
-// BuildFlags are flags that may be turned on during a build.
-type BuildFlags struct {
+// BuildState are flags that may be turned on during a build.
+type BuildState struct {
+	counter uint64
 }
 
-func NewBuildFlags() BuildFlags {
-	return BuildFlags{}
+func (b *BuildState) Incr() int {
+	return int(atomic.AddUint64(&b.counter, uint64(1)))
+}
+
+func NewBuildState() BuildState {
+	return BuildState{}
 }

deps/deps_test.go

@@ -15,8 +15,18 @@ package deps
 
 import (
 	"testing"
+
+	qt "github.com/frankban/quicktest"
 )
 
 func TestBuildFlags(t *testing.T) {
 
+	c := qt.New(t)
+	var bf BuildState
+	bf.Incr()
+	bf.Incr()
+	bf.Incr()
+
+	c.Assert(bf.Incr(), qt.Equals, 4)
+
 }

hugolib/filesystems/basefs.go

@@ -345,7 +345,7 @@ func NewBase(p *paths.Paths, logger *loggers.Logger, options ...func(*BaseFs) er
 		logger = loggers.NewWarningLogger()
 	}
 
-	publishFs := afero.NewBasePathFs(fs.Destination, p.AbsPublishDir)
+	publishFs := hugofs.NewBaseFileDecorator(afero.NewBasePathFs(fs.Destination, p.AbsPublishDir))
 
 	b := &BaseFs{
 		PublishFs: publishFs,

hugolib/hugo_sites_build.go

@@ -17,7 +17,17 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"os"
 	"runtime/trace"
+	"strings"
+
+	"github.com/gohugoio/hugo/common/para"
+	"github.com/gohugoio/hugo/config"
+	"github.com/gohugoio/hugo/resources/postpub"
+
+	"github.com/spf13/afero"
+
+	"github.com/gohugoio/hugo/resources/resource"
 
 	"github.com/gohugoio/hugo/output"
 
@@ -138,6 +148,10 @@ func (h *HugoSites) Build(config BuildCfg, events ...fsnotify.Event) error {
 		}
 	}
 
+	if err := h.postProcess(); err != nil {
+		h.SendError(err)
+	}
+
 	if h.Metrics != nil {
 		var b bytes.Buffer
 		h.Metrics.WriteMetrics(&b)
@@ -321,3 +335,90 @@ func (h *HugoSites) render(config *BuildCfg) error {
 
 	return nil
 }
+
+func (h *HugoSites) postProcess() error {
+	var toPostProcess []resource.OriginProvider
+	for _, s := range h.Sites {
+		for _, v := range s.ResourceSpec.PostProcessResources {
+			toPostProcess = append(toPostProcess, v)
+		}
+	}
+
+	if len(toPostProcess) == 0 {
+		return nil
+	}
+
+	workers := para.New(config.GetNumWorkerMultiplier())
+	g, _ := workers.Start(context.Background())
+
+	handleFile := func(filename string) error {
+
+		content, err := afero.ReadFile(h.BaseFs.PublishFs, filename)
+		if err != nil {
+			return err
+		}
+
+		k := 0
+		changed := false
+
+		for {
+			l := bytes.Index(content[k:], []byte(postpub.PostProcessPrefix))
+			if l == -1 {
+				break
+			}
+			m := bytes.Index(content[k+l:], []byte(postpub.PostProcessSuffix)) + len(postpub.PostProcessSuffix)
+
+			low, high := k+l, k+l+m
+
+			field := content[low:high]
+
+			forward := l + m
+
+			for i, r := range toPostProcess {
+				if r == nil {
+					panic(fmt.Sprintf("resource %d to post process is nil", i+1))
+				}
+				v, ok := r.GetFieldString(string(field))
+				if ok {
+					content = append(content[:low], append([]byte(v), content[high:]...)...)
+					changed = true
+					forward = len(v)
+					break
+				}
+			}
+
+			k += forward
+		}
+
+		if changed {
+			return afero.WriteFile(h.BaseFs.PublishFs, filename, content, 0666)
+		}
+
+		return nil
+
+	}
+
+	_ = afero.Walk(h.BaseFs.PublishFs, "", func(path string, info os.FileInfo, err error) error {
+		if info == nil || info.IsDir() {
+			return nil
+		}
+
+		if !strings.HasSuffix(path, "html") {
+			return nil
+		}
+
+		g.Run(func() error {
+			return handleFile(path)
+		})
+
+		return nil
+	})
+
+	// Prepare for a new build.
+	for _, s := range h.Sites {
+		s.ResourceSpec.PostProcessResources = make(map[string]postpub.PostPublishedResource)
+	}
+
+	return g.Wait()
+
+}

hugolib/page__common.go

@@ -86,7 +86,8 @@ type pageCommon struct {
 	resource.ResourceDataProvider
 	resource.ResourceMetaProvider
 	resource.ResourceParamsProvider
-	resource.ResourceTypesProvider
+	resource.ResourceTypeProvider
+	resource.MediaTypeProvider
 	resource.TranslationKeyProvider
 	compare.Eqer
 

hugolib/page__new.go

@@ -49,7 +49,8 @@ func newPageBase(metaProvider *pageMeta) (*pageState, error) {
 			PageMetaProvider:        metaProvider,
 			RelatedKeywordsProvider: metaProvider,
 			OutputFormatsProvider:   page.NopPage,
-			ResourceTypesProvider:   pageTypesProvider,
+			ResourceTypeProvider:    pageTypesProvider,
+			MediaTypeProvider:       pageTypesProvider,
 			RefProvider:             page.NopPage,
 			ShortcodeInfoProvider:   page.NopPage,
 			LanguageProvider:        s,

hugolib/resource_chain_test.go

@@ -14,13 +14,16 @@
 package hugolib
 
 import (
+	"fmt"
 	"io"
+	"math/rand"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/gohugoio/hugo/common/herrors"
 
@@ -352,6 +355,80 @@ Edited content.
 	}
 }
 
+func TestResourceChainPostProcess(t *testing.T) {
+	t.Parallel()
+
+	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
+
+	b := newTestSitesBuilder(t)
+	b.WithContent("page1.md", "---\ntitle: Page1\n---")
+	b.WithContent("page2.md", "---\ntitle: Page2\n---")
+
+	b.WithTemplates(
+		"_default/single.html", `{{ $hello := "<h1>     Hello World!   </h1>" | resources.FromString "hello.html" | minify  | fingerprint "md5" | resources.PostProcess }}
+HELLO: {{ $hello.RelPermalink }}	
+`,
+		"index.html", `Start.
+{{ $hello := "<h1>     Hello World!   </h1>" | resources.FromString "hello.html" | minify  | fingerprint "md5" | resources.PostProcess }}
+
+HELLO: {{ $hello.RelPermalink }}|Integrity: {{ $hello.Data.Integrity }}|MediaType: {{ $hello.MediaType.Type }}
+HELLO2: Name: {{ $hello.Name }}|Content: {{ $hello.Content }}|Title: {{ $hello.Title }}|ResourceType: {{ $hello.ResourceType }}
+
+`+strings.Repeat("a b", rnd.Intn(10)+1)+`
+
+
+End.`)
+
+	b.Running()
+	b.Build(BuildCfg{})
+	b.AssertFileContent("public/index.html",
+		`Start.
+HELLO: /hello.min.a2d1cb24f24b322a7dad520414c523e9.html|Integrity: md5-otHLJPJLMip9rVIEFMUj6Q==|MediaType: text/html
+HELLO2: Name: hello.html|Content: <h1>Hello World!</h1>|Title: hello.html|ResourceType: html
+End.`)
+
+	b.AssertFileContent("public/page1/index.html", `HELLO: /hello.min.a2d1cb24f24b322a7dad520414c523e9.html`)
+	b.AssertFileContent("public/page2/index.html", `HELLO: /hello.min.a2d1cb24f24b322a7dad520414c523e9.html`)
+
+}
+
+func BenchmarkResourceChainPostProcess(b *testing.B) {
+
+	for i := 0; i < b.N; i++ {
+		b.StopTimer()
+		s := newTestSitesBuilder(b)
+		for i := 0; i < 300; i++ {
+			s.WithContent(fmt.Sprintf("page%d.md", i+1), "---\ntitle: Page\n---")
+		}
+		s.WithTemplates("_default/single.html", `Start.
+Some text.
+
+
+{{ $hello1 := "<h1>     Hello World 2!   </h1>" | resources.FromString "hello.html" | minify  | fingerprint "md5" | resources.PostProcess }}
+{{ $hello2 := "<h1>     Hello World 2!   </h1>" | resources.FromString (printf "%s.html" .Path) | minify  | fingerprint "md5" | resources.PostProcess }}
+
+Some more text.
+
+HELLO: {{ $hello1.RelPermalink }}|Integrity: {{ $hello1.Data.Integrity }}|MediaType: {{ $hello1.MediaType.Type }}
+
+Some more text.
+
+HELLO2: Name: {{ $hello2.Name }}|Content: {{ $hello2.Content }}|Title: {{ $hello2.Title }}|ResourceType: {{ $hello2.ResourceType }}
+
+Some more text.
+
+HELLO2_2: Name: {{ $hello2.Name }}|Content: {{ $hello2.Content }}|Title: {{ $hello2.Title }}|ResourceType: {{ $hello2.ResourceType }}
+
+End.
+`)
+
+		b.StartTimer()
+		s.Build(BuildCfg{})
+
+	}
+
+}
+
 func TestResourceChains(t *testing.T) {
 	t.Parallel()
 
@@ -769,7 +846,6 @@ func TestResourceChainPostCSS(t *testing.T) {
 	}
 
 	if runtime.GOOS == "windows" {
-		// TODO(bep)
 		t.Skip("skip npm test on Windows")
 	}
 

identity/identity.go

@@ -4,6 +4,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"sync/atomic"
 )
 
 // NewIdentityManager creates a new Manager starting at id.
@@ -139,3 +140,18 @@ func (im *identityManager) Search(id Identity) Provider {
 	defer im.Unlock()
 	return im.ids.search(0, id.GetIdentity())
 }
+
+// Incrementer increments and returns the value.
+// Typically used for IDs.
+type Incrementer interface {
+	Incr() int
+}
+
+// IncrementByOne implements Incrementer adding 1 every time Incr is called.
+type IncrementByOne struct {
+	counter uint64
+}
+
+func (c *IncrementByOne) Incr() int {
+	return int(atomic.AddUint64(&c.counter, uint64(1)))
+}

resources/post_publish.go

@@ -0,0 +1,51 @@
+// Copyright 2020 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 resources
+
+import (
+	"github.com/gohugoio/hugo/resources/postpub"
+	"github.com/gohugoio/hugo/resources/resource"
+)
+
+type transformationKeyer interface {
+	TransformationKey() string
+}
+
+// PostProcess wraps the given Resource for later processing.
+func (spec *Spec) PostProcess(r resource.Resource) (postpub.PostPublishedResource, error) {
+	key := r.(transformationKeyer).TransformationKey()
+	spec.postProcessMu.RLock()
+	result, found := spec.PostProcessResources[key]
+	spec.postProcessMu.RUnlock()
+	if found {
+		return result, nil
+	}
+
+	spec.postProcessMu.Lock()
+	defer spec.postProcessMu.Unlock()
+
+	// Double check
+	result, found = spec.PostProcessResources[key]
+	if found {
+		return result, nil
+	}
+
+	result = postpub.NewPostPublishResource(spec.incr.Incr(), r)
+	if result == nil {
+		panic("got nil result")
+	}
+	spec.PostProcessResources[key] = result
+
+	return result, nil
+}

resources/postpub/fields.go

@@ -0,0 +1,59 @@
+// Copyright 2020 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 postpub
+
+import (
+	"reflect"
+)
+
+const (
+	FieldNotSupported = "__field_not_supported"
+)
+
+func structToMapWithPlaceholders(root string, in interface{}, createPlaceholder func(s string) string) map[string]interface{} {
+	m := structToMap(in)
+	insertFieldPlaceholders(root, m, createPlaceholder)
+	return m
+}
+
+func structToMap(s interface{}) map[string]interface{} {
+	m := make(map[string]interface{})
+	t := reflect.TypeOf(s)
+
+	for i := 0; i < t.NumMethod(); i++ {
+		method := t.Method(i)
+		if method.PkgPath != "" {
+			continue
+		}
+		if method.Type.NumIn() == 1 {
+			m[method.Name] = ""
+		}
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		if field.PkgPath != "" {
+			continue
+		}
+		m[field.Name] = ""
+	}
+	return m
+}
+
+// insert placeholder for the templates. Do it very shallow for now.
+func insertFieldPlaceholders(root string, m map[string]interface{}, createPlaceholder func(s string) string) {
+	for k, _ := range m {
+		m[k] = createPlaceholder(root + "." + k)
+	}
+}

resources/postpub/fields_test.go

@@ -0,0 +1,45 @@
+// Copyright 2020 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 postpub
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+
+	"github.com/gohugoio/hugo/media"
+)
+
+func TestCreatePlaceholders(t *testing.T) {
+	c := qt.New(t)
+
+	m := structToMap(media.CSSType)
+
+	insertFieldPlaceholders("foo", m, func(s string) string {
+		return "pre_" + s + "_post"
+	})
+
+	c.Assert(m, qt.DeepEquals, map[string]interface{}{
+		"FullSuffix":  "pre_foo.FullSuffix_post",
+		"Type":        "pre_foo.Type_post",
+		"MainType":    "pre_foo.MainType_post",
+		"Delimiter":   "pre_foo.Delimiter_post",
+		"MarshalJSON": "pre_foo.MarshalJSON_post",
+		"String":      "pre_foo.String_post",
+		"Suffix":      "pre_foo.Suffix_post",
+		"SubType":     "pre_foo.SubType_post",
+		"Suffixes":    "pre_foo.Suffixes_post",
+	})
+
+}

resources/postpub/postpub.go

@@ -0,0 +1,177 @@
+// Copyright 2020 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 postpub
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"github.com/spf13/cast"
+
+	"github.com/gohugoio/hugo/common/maps"
+	"github.com/gohugoio/hugo/media"
+	"github.com/gohugoio/hugo/resources/resource"
+)
+
+type PostPublishedResource interface {
+	resource.ResourceTypeProvider
+	resource.ResourceLinksProvider
+	resource.ResourceMetaProvider
+	resource.ResourceParamsProvider
+	resource.ResourceDataProvider
+	resource.OriginProvider
+
+	MediaType() map[string]interface{}
+}
+
+const (
+	PostProcessPrefix = "__h_pp_l1"
+	PostProcessSuffix = "__e"
+)
+
+func NewPostPublishResource(id int, r resource.Resource) PostPublishedResource {
+	return &PostPublishResource{
+		prefix:   PostProcessPrefix + "_" + strconv.Itoa(id) + "_",
+		delegate: r,
+	}
+}
+
+// postPublishResource holds a Resource to be transformed post publishing.
+type PostPublishResource struct {
+	prefix   string
+	delegate resource.Resource
+}
+
+func (r *PostPublishResource) field(name string) string {
+	return r.prefix + name + PostProcessSuffix
+}
+
+func (r *PostPublishResource) Permalink() string {
+	return r.field("Permalink")
+}
+
+func (r *PostPublishResource) RelPermalink() string {
+	return r.field("RelPermalink")
+}
+
+func (r *PostPublishResource) Origin() resource.Resource {
+	return r.delegate
+}
+
+func (r *PostPublishResource) GetFieldString(pattern string) (string, bool) {
+	if r == nil {
+		panic("resource is nil")
+	}
+	prefixIdx := strings.Index(pattern, r.prefix)
+	if prefixIdx == -1 {
+		// Not a method on this resource.
+		return "", false
+	}
+
+	fieldAccessor := pattern[prefixIdx+len(r.prefix) : strings.Index(pattern, PostProcessSuffix)]
+
+	d := r.delegate
+	switch {
+	case fieldAccessor == "RelPermalink":
+		return d.RelPermalink(), true
+	case fieldAccessor == "Permalink":
+		return d.Permalink(), true
+	case fieldAccessor == "Name":
+		return d.Name(), true
+	case fieldAccessor == "Title":
+		return d.Title(), true
+	case fieldAccessor == "ResourceType":
+		return d.ResourceType(), true
+	case fieldAccessor == "Content":
+		content, err := d.(resource.ContentProvider).Content()
+		if err != nil {
+			return "", true
+		}
+		return cast.ToString(content), true
+	case strings.HasPrefix(fieldAccessor, "MediaType"):
+		return r.fieldToString(d.MediaType(), fieldAccessor), true
+	case fieldAccessor == "Data.Integrity":
+		return cast.ToString((d.Data().(map[string]interface{})["Integrity"])), true
+	default:
+		panic(fmt.Sprintf("unknown field accessor %q", fieldAccessor))
+	}
+
+}
+
+func (r *PostPublishResource) fieldToString(receiver interface{}, path string) string {
+	fieldname := strings.Split(path, ".")[1]
+
+	receiverv := reflect.ValueOf(receiver)
+	switch receiverv.Kind() {
+	case reflect.Map:
+		v := receiverv.MapIndex(reflect.ValueOf(fieldname))
+		return cast.ToString(v.Interface())
+	default:
+		v := receiverv.FieldByName(fieldname)
+		if !v.IsValid() {
+			method := receiverv.MethodByName(fieldname)
+			if method.IsValid() {
+				vals := method.Call(nil)
+				if len(vals) > 0 {
+					v = vals[0]
+				}
+
+			}
+		}
+
+		if v.IsValid() {
+			return cast.ToString(v.Interface())
+		}
+		return ""
+	}
+}
+
+func (r *PostPublishResource) Data() interface{} {
+	m := map[string]interface{}{
+		"Integrity": "",
+	}
+	insertFieldPlaceholders("Data", m, r.field)
+	return m
+}
+
+func (r *PostPublishResource) MediaType() map[string]interface{} {
+	m := structToMapWithPlaceholders("MediaType", media.Type{}, r.field)
+	return m
+}
+
+func (r *PostPublishResource) ResourceType() string {
+	return r.field("ResourceType")
+}
+
+func (r *PostPublishResource) Name() string {
+	return r.field("Name")
+}
+
+func (r *PostPublishResource) Title() string {
+	return r.field("Title")
+}
+
+func (r *PostPublishResource) Params() maps.Params {
+	panic(r.fieldNotSupported("Params"))
+}
+
+func (r *PostPublishResource) Content() (interface{}, error) {
+	return r.field("Content"), nil
+}
+
+func (r *PostPublishResource) fieldNotSupported(name string) string {
+	return fmt.Sprintf("method .%s is currently not supported in post-publish transformations.", name)
+}

resources/resource/resourcetypes.go

@@ -28,9 +28,17 @@ type Cloner interface {
 	Clone() Resource
 }
 
+// OriginProvider provides the original Resource if this is wrapped.
+// This is an internal Hugo interface and not meant for use in the templates.
+type OriginProvider interface {
+	Origin() Resource
+	GetFieldString(pattern string) (string, bool)
+}
+
 // Resource represents a linkable resource, i.e. a content page, image etc.
 type Resource interface {
-	ResourceTypesProvider
+	ResourceTypeProvider
+	MediaTypeProvider
 	ResourceLinksProvider
 	ResourceMetaProvider
 	ResourceParamsProvider
@@ -53,16 +61,23 @@ type ImageOps interface {
 	Exif() (*exif.Exif, error)
 }
 
-type ResourceTypesProvider interface {
-	// MediaType is this resource's MIME type.
-	MediaType() media.Type
-
+type ResourceTypeProvider interface {
 	// ResourceType is the resource type. For most file types, this is the main
 	// part of the MIME type, e.g. "image", "application", "text" etc.
 	// For content pages, this value is "page".
 	ResourceType() string
 }
 
+type ResourceTypesProvider interface {
+	ResourceTypeProvider
+	MediaTypeProvider
+}
+
+type MediaTypeProvider interface {
+	// MediaType is this resource's MIME type.
+	MediaType() media.Type
+}
+
 type ResourceLinksProvider interface {
 	// Permalink represents the absolute link to this resource.
 	Permalink() string

resources/resource_spec.go

@@ -21,14 +21,16 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
+	"sync"
 
 	"github.com/gohugoio/hugo/common/herrors"
 
 	"github.com/gohugoio/hugo/config"
-
-	"github.com/gohugoio/hugo/hugofs"
+	"github.com/gohugoio/hugo/identity"
 
 	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/hugofs"
+	"github.com/gohugoio/hugo/resources/postpub"
 
 	"github.com/gohugoio/hugo/cache/filecache"
 	"github.com/gohugoio/hugo/common/loggers"
@@ -44,6 +46,7 @@ import (
 func NewSpec(
 	s *helpers.PathSpec,
 	fileCaches filecache.Caches,
+	incr identity.Incrementer,
 	logger *loggers.Logger,
 	errorHandler herrors.ErrorSender,
 	outputFormats output.Formats,
@@ -59,6 +62,10 @@ func NewSpec(
 		return nil, err
 	}
 
+	if incr == nil {
+		incr = &identity.IncrementByOne{}
+	}
+
 	if logger == nil {
 		logger = loggers.NewErrorLogger()
 	}
@@ -68,15 +75,18 @@ func NewSpec(
 		return nil, err
 	}
 
-	rs := &Spec{PathSpec: s,
-		Logger:        logger,
-		ErrorSender:   errorHandler,
-		imaging:       imaging,
-		MediaTypes:    mimeTypes,
-		OutputFormats: outputFormats,
-		Permalinks:    permalinks,
-		BuildConfig:   config.DecodeBuild(s.Cfg),
-		FileCaches:    fileCaches,
+	rs := &Spec{
+		PathSpec:             s,
+		Logger:               logger,
+		ErrorSender:          errorHandler,
+		imaging:              imaging,
+		incr:                 incr,
+		MediaTypes:           mimeTypes,
+		OutputFormats:        outputFormats,
+		Permalinks:           permalinks,
+		BuildConfig:          config.DecodeBuild(s.Cfg),
+		FileCaches:           fileCaches,
+		PostProcessResources: make(map[string]postpub.PostPublishedResource),
 		imageCache: newImageCache(
 			fileCaches.ImageCache(),
 
@@ -106,9 +116,13 @@ type Spec struct {
 	// Holds default filter settings etc.
 	imaging *images.ImageProcessor
 
+	incr          identity.Incrementer
 	imageCache    *imageCache
 	ResourceCache *ResourceCache
 	FileCaches    filecache.Caches
+
+	postProcessMu        sync.RWMutex
+	PostProcessResources map[string]postpub.PostPublishedResource
 }
 
 func (r *Spec) New(fd ResourceSourceDescriptor) (resource.Resource, error) {

resources/resource_transformers/htesting/testhelpers.go

@@ -51,7 +51,7 @@ func NewTestResourceSpec() (*resources.Spec, error) {
 		return nil, err
 	}
 
-	spec, err := resources.NewSpec(s, filecaches, nil, nil, output.DefaultFormats, media.DefaultTypes)
+	spec, err := resources.NewSpec(s, filecaches, nil, nil, nil, output.DefaultFormats, media.DefaultTypes)
 	return spec, err
 }
 

resources/testhelpers_test.go

@@ -90,7 +90,7 @@ func newTestResourceSpec(desc specDescriptor) *Spec {
 	filecaches, err := filecache.NewCaches(s)
 	c.Assert(err, qt.IsNil)
 
-	spec, err := NewSpec(s, filecaches, nil, nil, output.DefaultFormats, media.DefaultTypes)
+	spec, err := NewSpec(s, filecaches, nil, nil, nil, output.DefaultFormats, media.DefaultTypes)
 	c.Assert(err, qt.IsNil)
 	return spec
 }
@@ -129,7 +129,7 @@ func newTestResourceOsFs(c *qt.C) (*Spec, string) {
 	filecaches, err := filecache.NewCaches(s)
 	c.Assert(err, qt.IsNil)
 
-	spec, err := NewSpec(s, filecaches, nil, nil, output.DefaultFormats, media.DefaultTypes)
+	spec, err := NewSpec(s, filecaches, nil, nil, nil, output.DefaultFormats, media.DefaultTypes)
 	c.Assert(err, qt.IsNil)
 
 	return spec, workDir

resources/transform.go

@@ -296,9 +296,7 @@ func (r *resourceAdapter) publish() {
 
 }
 
-func (r *resourceAdapter) transform(publish, setContent bool) error {
-	cache := r.spec.ResourceCache
-
+func (r *resourceAdapter) TransformationKey() string {
 	// Files with a suffix will be stored in cache (both on disk and in memory)
 	// partitioned by their suffix.
 	var key string
@@ -307,8 +305,13 @@ func (r *resourceAdapter) transform(publish, setContent bool) error {
 	}
 
 	base := ResourceCacheKey(r.target.Key())
+	return r.spec.ResourceCache.cleanKey(base) + "_" + helpers.MD5String(key)
+}
 
-	key = cache.cleanKey(base) + "_" + helpers.MD5String(key)
+func (r *resourceAdapter) transform(publish, setContent bool) error {
+	cache := r.spec.ResourceCache
+
+	key := r.TransformationKey()
 
 	cached, found := cache.get(key)
 

tpl/resources/resources.go

@@ -19,6 +19,8 @@ import (
 	"fmt"
 	"path/filepath"
 
+	"github.com/gohugoio/hugo/resources/postpub"
+
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/resources"
@@ -273,6 +275,10 @@ func (ns *Namespace) PostCSS(args ...interface{}) (resource.Resource, error) {
 	return ns.postcssClient.Process(r, options)
 }
 
+func (ns *Namespace) PostProcess(r resource.Resource) (postpub.PostPublishedResource, error) {
+	return ns.deps.ResourceSpec.PostProcess(r)
+}
+
 // We allow string or a map as the first argument in some cases.
 func (ns *Namespace) resolveIfFirstArgIsString(args []interface{}) (resources.ResourceTransformer, string, bool) {
 	if len(args) != 2 {