gotosocial/internal/ap/collections.go

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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package ap
import (
"fmt"
"net/url"
"github.com/superseriousbusiness/activity/streams"
"github.com/superseriousbusiness/activity/streams/vocab"
"github.com/superseriousbusiness/gotosocial/internal/paging"
)
// ToCollectionPageIterator attempts to resolve the given vocab type as a CollectionPage
// like object and wrap in a standardised interface in order to iterate its contents.
func ToCollectionPageIterator(t vocab.Type) (CollectionPageIterator, error) {
switch name := t.GetTypeName(); name {
case ObjectCollectionPage:
t := t.(vocab.ActivityStreamsCollectionPage)
return WrapCollectionPage(t), nil
case ObjectOrderedCollectionPage:
t := t.(vocab.ActivityStreamsOrderedCollectionPage)
return WrapOrderedCollectionPage(t), nil
default:
return nil, fmt.Errorf("%T(%s) was not CollectionPage-like", t, name)
}
}
// WrapCollectionPage wraps an ActivityStreamsCollectionPage in a standardised collection page interface.
func WrapCollectionPage(page vocab.ActivityStreamsCollectionPage) CollectionPageIterator {
return &regularCollectionPageIterator{ActivityStreamsCollectionPage: page}
}
// WrapOrderedCollectionPage wraps an ActivityStreamsOrderedCollectionPage in a standardised collection page interface.
func WrapOrderedCollectionPage(page vocab.ActivityStreamsOrderedCollectionPage) CollectionPageIterator {
return &orderedCollectionPageIterator{ActivityStreamsOrderedCollectionPage: page}
}
// regularCollectionPageIterator implements CollectionPageIterator
// for the vocab.ActivitiyStreamsCollectionPage type.
type regularCollectionPageIterator struct {
vocab.ActivityStreamsCollectionPage
items vocab.ActivityStreamsItemsPropertyIterator
once bool // only init items once
}
func (iter *regularCollectionPageIterator) NextPage() WithIRI {
if iter.ActivityStreamsCollectionPage == nil {
return nil
}
return iter.GetActivityStreamsNext()
}
func (iter *regularCollectionPageIterator) PrevPage() WithIRI {
if iter.ActivityStreamsCollectionPage == nil {
return nil
}
return iter.GetActivityStreamsPrev()
}
func (iter *regularCollectionPageIterator) NextItem() TypeOrIRI {
if !iter.initItems() {
return nil
}
cur := iter.items
iter.items = iter.items.Next()
return cur
}
func (iter *regularCollectionPageIterator) PrevItem() TypeOrIRI {
if !iter.initItems() {
return nil
}
cur := iter.items
iter.items = iter.items.Prev()
return cur
}
func (iter *regularCollectionPageIterator) initItems() bool {
if iter.once {
return (iter.items != nil)
}
iter.once = true
if iter.ActivityStreamsCollectionPage == nil {
return false // no page set
}
items := iter.GetActivityStreamsItems()
if items == nil {
return false // no items found
}
iter.items = items.Begin()
return (iter.items != nil)
}
// orderedCollectionPageIterator implements CollectionPageIterator
// for the vocab.ActivitiyStreamsOrderedCollectionPage type.
type orderedCollectionPageIterator struct {
vocab.ActivityStreamsOrderedCollectionPage
items vocab.ActivityStreamsOrderedItemsPropertyIterator
once bool // only init items once
}
func (iter *orderedCollectionPageIterator) NextPage() WithIRI {
if iter.ActivityStreamsOrderedCollectionPage == nil {
return nil
}
return iter.GetActivityStreamsNext()
}
func (iter *orderedCollectionPageIterator) PrevPage() WithIRI {
if iter.ActivityStreamsOrderedCollectionPage == nil {
return nil
}
return iter.GetActivityStreamsPrev()
}
func (iter *orderedCollectionPageIterator) NextItem() TypeOrIRI {
if !iter.initItems() {
return nil
}
cur := iter.items
iter.items = iter.items.Next()
return cur
}
func (iter *orderedCollectionPageIterator) PrevItem() TypeOrIRI {
if !iter.initItems() {
return nil
}
cur := iter.items
iter.items = iter.items.Prev()
return cur
}
func (iter *orderedCollectionPageIterator) initItems() bool {
if iter.once {
return (iter.items != nil)
}
iter.once = true
if iter.ActivityStreamsOrderedCollectionPage == nil {
return false // no page set
}
items := iter.GetActivityStreamsOrderedItems()
if items == nil {
return false // no items found
}
iter.items = items.Begin()
return (iter.items != nil)
}
type CollectionParams struct {
// Containing collection
// ID (i.e. NOT the page).
ID *url.URL
// First page details.
First paging.Page
Query url.Values
// Total no. items.
Total int
}
type CollectionPageParams struct {
// containing collection.
CollectionParams
// Paging details.
Current *paging.Page
Next *paging.Page
Prev *paging.Page
Query url.Values
// Item appender for each item at index.
Append func(int, ItemsPropertyBuilder)
Count int
}
// CollectionPage is a simplified interface type
// that can be fulfilled by either of (where required):
// vocab.ActivityStreamsCollection
// vocab.ActivityStreamsOrderedCollection
type CollectionBuilder interface {
SetJSONLDId(vocab.JSONLDIdProperty)
SetActivityStreamsFirst(vocab.ActivityStreamsFirstProperty)
SetActivityStreamsTotalItems(i vocab.ActivityStreamsTotalItemsProperty)
}
// CollectionPageBuilder is a simplified interface type
// that can be fulfilled by either of (where required):
// vocab.ActivityStreamsCollectionPage
// vocab.ActivityStreamsOrderedCollectionPage
type CollectionPageBuilder interface {
SetJSONLDId(vocab.JSONLDIdProperty)
SetActivityStreamsPartOf(vocab.ActivityStreamsPartOfProperty)
SetActivityStreamsNext(vocab.ActivityStreamsNextProperty)
SetActivityStreamsPrev(vocab.ActivityStreamsPrevProperty)
SetActivityStreamsTotalItems(i vocab.ActivityStreamsTotalItemsProperty)
}
// ItemsPropertyBuilder is a simplified interface type
// that can be fulfilled by either of (where required):
// vocab.ActivityStreamsItemsProperty
// vocab.ActivityStreamsOrderedItemsProperty
type ItemsPropertyBuilder interface {
AppendIRI(*url.URL)
// NOTE: add more of the items-property-like interface
// functions here as you require them for building pages.
}
// NewASCollection builds and returns a new ActivityStreams Collection from given parameters.
func NewASCollection(params CollectionParams) vocab.ActivityStreamsCollection {
collection := streams.NewActivityStreamsCollection()
buildCollection(collection, params)
return collection
}
// NewASCollectionPage builds and returns a new ActivityStreams CollectionPage from given parameters (including item property appending function).
func NewASCollectionPage(params CollectionPageParams) vocab.ActivityStreamsCollectionPage {
collectionPage := streams.NewActivityStreamsCollectionPage()
itemsProp := streams.NewActivityStreamsItemsProperty()
buildCollectionPage(collectionPage, itemsProp, collectionPage.SetActivityStreamsItems, params)
return collectionPage
}
// NewASOrderedCollection builds and returns a new ActivityStreams OrderedCollection from given parameters.
func NewASOrderedCollection(params CollectionParams) vocab.ActivityStreamsOrderedCollection {
collection := streams.NewActivityStreamsOrderedCollection()
buildCollection(collection, params)
return collection
}
// NewASOrderedCollectionPage builds and returns a new ActivityStreams OrderedCollectionPage from given parameters (including item property appending function).
func NewASOrderedCollectionPage(params CollectionPageParams) vocab.ActivityStreamsOrderedCollectionPage {
collectionPage := streams.NewActivityStreamsOrderedCollectionPage()
itemsProp := streams.NewActivityStreamsOrderedItemsProperty()
buildCollectionPage(collectionPage, itemsProp, collectionPage.SetActivityStreamsOrderedItems, params)
return collectionPage
}
func buildCollection[C CollectionBuilder](collection C, params CollectionParams) {
// Add the collection ID property.
idProp := streams.NewJSONLDIdProperty()
idProp.SetIRI(params.ID)
collection.SetJSONLDId(idProp)
// Add the collection totalItems count property.
totalItems := streams.NewActivityStreamsTotalItemsProperty()
totalItems.Set(params.Total)
collection.SetActivityStreamsTotalItems(totalItems)
// Append paging query params
// to those already in ID prop.
pageQueryParams := appendQuery(
params.Query,
params.ID.Query(),
)
// Build the first page link IRI.
firstIRI := params.First.ToLinkURL(
params.ID.Scheme,
params.ID.Host,
params.ID.Path,
pageQueryParams,
)
// Add the collection first IRI property.
first := streams.NewActivityStreamsFirstProperty()
first.SetIRI(firstIRI)
collection.SetActivityStreamsFirst(first)
}
func buildCollectionPage[C CollectionPageBuilder, I ItemsPropertyBuilder](collectionPage C, itemsProp I, setItems func(I), params CollectionPageParams) {
// Add the partOf property for its containing collection ID.
partOfProp := streams.NewActivityStreamsPartOfProperty()
partOfProp.SetIRI(params.ID)
collectionPage.SetActivityStreamsPartOf(partOfProp)
// Append paging query params
// to those already in ID prop.
pageQueryParams := appendQuery(
params.Query,
params.ID.Query(),
)
// Build the current page link IRI.
currentIRI := params.Current.ToLinkURL(
params.ID.Scheme,
params.ID.Host,
params.ID.Path,
pageQueryParams,
)
// Add the collection ID property for
// the *current* collection page params.
idProp := streams.NewJSONLDIdProperty()
idProp.SetIRI(currentIRI)
collectionPage.SetJSONLDId(idProp)
// Build the next page link IRI.
nextIRI := params.Next.ToLinkURL(
params.ID.Scheme,
params.ID.Host,
params.ID.Path,
pageQueryParams,
)
if nextIRI != nil {
// Add the collection next property for the next page.
nextProp := streams.NewActivityStreamsNextProperty()
nextProp.SetIRI(nextIRI)
collectionPage.SetActivityStreamsNext(nextProp)
}
// Build the prev page link IRI.
prevIRI := params.Prev.ToLinkURL(
params.ID.Scheme,
params.ID.Host,
params.ID.Path,
pageQueryParams,
)
if prevIRI != nil {
// Add the collection prev property for the prev page.
prevProp := streams.NewActivityStreamsPrevProperty()
prevProp.SetIRI(prevIRI)
collectionPage.SetActivityStreamsPrev(prevProp)
}
// Add the collection totalItems count property.
totalItems := streams.NewActivityStreamsTotalItemsProperty()
totalItems.Set(params.Total)
collectionPage.SetActivityStreamsTotalItems(totalItems)
if params.Append == nil {
// nil check outside the for loop.
panic("nil params.Append function")
}
// Append each of the items to the provided
// pre-allocated items property builder type.
for i := 0; i < params.Count; i++ {
params.Append(i, itemsProp)
}
// Set the collection
// page items property.
setItems(itemsProp)
}
// appendQuery appends query values in 'src' to 'dst', returning 'dst'.
func appendQuery(dst, src url.Values) url.Values {
if dst == nil {
return src
}
for k, vs := range src {
dst[k] = append(dst[k], vs...)
}
return dst
}