GoToSocial/internal/ap/extract.go

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/*
GoToSocial
2021-12-20 18:42:19 +01:00
Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
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 contains models and utilities for working with activitypub/activitystreams representations.
//
// It is built on top of go-fed/activity.
package ap
import (
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"net/url"
"strings"
"time"
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"github.com/superseriousbusiness/activity/pub"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/util"
)
// ExtractPreferredUsername returns a string representation of an interface's preferredUsername property.
func ExtractPreferredUsername(i WithPreferredUsername) (string, error) {
u := i.GetActivityStreamsPreferredUsername()
if u == nil || !u.IsXMLSchemaString() {
return "", errors.New("preferredUsername was not a string")
}
if u.GetXMLSchemaString() == "" {
return "", errors.New("preferredUsername was empty")
}
return u.GetXMLSchemaString(), nil
}
// ExtractName returns a string representation of an interface's name property.
func ExtractName(i WithName) (string, error) {
nameProp := i.GetActivityStreamsName()
if nameProp == nil {
return "", errors.New("activityStreamsName not found")
}
// take the first name string we can find
for iter := nameProp.Begin(); iter != nameProp.End(); iter = iter.Next() {
if iter.IsXMLSchemaString() && iter.GetXMLSchemaString() != "" {
return iter.GetXMLSchemaString(), nil
}
}
return "", errors.New("activityStreamsName not found")
}
// ExtractInReplyToURI extracts the inReplyToURI property (if present) from an interface.
func ExtractInReplyToURI(i WithInReplyTo) *url.URL {
inReplyToProp := i.GetActivityStreamsInReplyTo()
if inReplyToProp == nil {
// the property just wasn't set
return nil
}
for iter := inReplyToProp.Begin(); iter != inReplyToProp.End(); iter = iter.Next() {
if iter.IsIRI() {
if iter.GetIRI() != nil {
return iter.GetIRI()
}
}
}
// couldn't find a URI
return nil
}
// ExtractURLItems extracts a slice of URLs from a property that has withItems.
func ExtractURLItems(i WithItems) []*url.URL {
urls := []*url.URL{}
items := i.GetActivityStreamsItems()
if items == nil || items.Len() == 0 {
return urls
}
for iter := items.Begin(); iter != items.End(); iter = iter.Next() {
if iter.IsIRI() {
urls = append(urls, iter.GetIRI())
}
}
return urls
}
// ExtractTos returns a list of URIs that the activity addresses as To.
func ExtractTos(i WithTo) ([]*url.URL, error) {
to := []*url.URL{}
toProp := i.GetActivityStreamsTo()
if toProp == nil {
return nil, errors.New("toProp was nil")
}
for iter := toProp.Begin(); iter != toProp.End(); iter = iter.Next() {
if iter.IsIRI() {
if iter.GetIRI() != nil {
to = append(to, iter.GetIRI())
}
}
}
return to, nil
}
// ExtractCCs returns a list of URIs that the activity addresses as CC.
func ExtractCCs(i WithCC) ([]*url.URL, error) {
cc := []*url.URL{}
ccProp := i.GetActivityStreamsCc()
if ccProp == nil {
return cc, nil
}
for iter := ccProp.Begin(); iter != ccProp.End(); iter = iter.Next() {
if iter.IsIRI() {
if iter.GetIRI() != nil {
cc = append(cc, iter.GetIRI())
}
}
}
return cc, nil
}
// ExtractAttributedTo returns the URL of the actor that the withAttributedTo is attributed to.
func ExtractAttributedTo(i WithAttributedTo) (*url.URL, error) {
attributedToProp := i.GetActivityStreamsAttributedTo()
if attributedToProp == nil {
return nil, errors.New("attributedToProp was nil")
}
for iter := attributedToProp.Begin(); iter != attributedToProp.End(); iter = iter.Next() {
if iter.IsIRI() {
if iter.GetIRI() != nil {
return iter.GetIRI(), nil
}
}
}
return nil, errors.New("couldn't find iri for attributed to")
}
// ExtractPublished extracts the publication time of an activity.
func ExtractPublished(i WithPublished) (time.Time, error) {
publishedProp := i.GetActivityStreamsPublished()
if publishedProp == nil {
return time.Time{}, errors.New("published prop was nil")
}
if !publishedProp.IsXMLSchemaDateTime() {
return time.Time{}, errors.New("published prop was not date time")
}
t := publishedProp.Get()
if t.IsZero() {
return time.Time{}, errors.New("published time was zero")
}
return t, nil
}
// ExtractIconURL extracts a URL to a supported image file from something like:
// "icon": {
// "mediaType": "image/jpeg",
// "type": "Image",
// "url": "http://example.org/path/to/some/file.jpeg"
// },
func ExtractIconURL(i WithIcon) (*url.URL, error) {
iconProp := i.GetActivityStreamsIcon()
if iconProp == nil {
return nil, errors.New("icon property was nil")
}
// icon can potentially contain multiple entries, so we iterate through all of them
// here in order to find the first one that meets these criteria:
// 1. is an image
// 2. has a URL so we can grab it
for iter := iconProp.Begin(); iter != iconProp.End(); iter = iter.Next() {
// 1. is an image
if !iter.IsActivityStreamsImage() {
continue
}
imageValue := iter.GetActivityStreamsImage()
if imageValue == nil {
continue
}
// 2. has a URL so we can grab it
url, err := ExtractURL(imageValue)
if err == nil && url != nil {
return url, nil
}
}
// if we get to this point we didn't find an icon meeting our criteria :'(
return nil, errors.New("could not extract valid image from icon")
}
// ExtractImageURL extracts a URL to a supported image file from something like:
// "image": {
// "mediaType": "image/jpeg",
// "type": "Image",
// "url": "http://example.org/path/to/some/file.jpeg"
// },
func ExtractImageURL(i WithImage) (*url.URL, error) {
imageProp := i.GetActivityStreamsImage()
if imageProp == nil {
return nil, errors.New("icon property was nil")
}
// icon can potentially contain multiple entries, so we iterate through all of them
// here in order to find the first one that meets these criteria:
// 1. is an image
// 2. has a URL so we can grab it
for iter := imageProp.Begin(); iter != imageProp.End(); iter = iter.Next() {
// 1. is an image
if !iter.IsActivityStreamsImage() {
continue
}
imageValue := iter.GetActivityStreamsImage()
if imageValue == nil {
continue
}
// 2. has a URL so we can grab it
url, err := ExtractURL(imageValue)
if err == nil && url != nil {
return url, nil
}
}
// if we get to this point we didn't find an image meeting our criteria :'(
return nil, errors.New("could not extract valid image from image property")
}
// ExtractSummary extracts the summary/content warning of an interface.
func ExtractSummary(i WithSummary) (string, error) {
summaryProp := i.GetActivityStreamsSummary()
if summaryProp == nil || summaryProp.Len() == 0 {
// no summary to speak of
return "", nil
}
for iter := summaryProp.Begin(); iter != summaryProp.End(); iter = iter.Next() {
if iter.IsXMLSchemaString() && iter.GetXMLSchemaString() != "" {
return iter.GetXMLSchemaString(), nil
}
}
return "", nil
}
// ExtractDiscoverable extracts the Discoverable boolean of an interface.
func ExtractDiscoverable(i WithDiscoverable) (bool, error) {
if i.GetTootDiscoverable() == nil {
return false, errors.New("discoverable was nil")
}
return i.GetTootDiscoverable().Get(), nil
}
// ExtractURL extracts the URL property of an interface.
func ExtractURL(i WithURL) (*url.URL, error) {
urlProp := i.GetActivityStreamsUrl()
if urlProp == nil {
return nil, errors.New("url property was nil")
}
for iter := urlProp.Begin(); iter != urlProp.End(); iter = iter.Next() {
if iter.IsIRI() && iter.GetIRI() != nil {
return iter.GetIRI(), nil
}
}
return nil, errors.New("could not extract url")
}
// ExtractPublicKeyForOwner extracts the public key from an interface, as long as it belongs to the specified owner.
// It will return the public key itself, the id/URL of the public key, or an error if something goes wrong.
func ExtractPublicKeyForOwner(i WithPublicKey, forOwner *url.URL) (*rsa.PublicKey, *url.URL, error) {
publicKeyProp := i.GetW3IDSecurityV1PublicKey()
if publicKeyProp == nil {
return nil, nil, errors.New("public key property was nil")
}
for iter := publicKeyProp.Begin(); iter != publicKeyProp.End(); iter = iter.Next() {
pkey := iter.Get()
if pkey == nil {
continue
}
pkeyID, err := pub.GetId(pkey)
if err != nil || pkeyID == nil {
continue
}
if pkey.GetW3IDSecurityV1Owner() == nil || pkey.GetW3IDSecurityV1Owner().Get() == nil || pkey.GetW3IDSecurityV1Owner().Get().String() != forOwner.String() {
continue
}
if pkey.GetW3IDSecurityV1PublicKeyPem() == nil {
continue
}
pkeyPem := pkey.GetW3IDSecurityV1PublicKeyPem().Get()
if pkeyPem == "" {
continue
}
block, _ := pem.Decode([]byte(pkeyPem))
if block == nil || block.Type != "PUBLIC KEY" {
return nil, nil, errors.New("could not decode publicKeyPem to PUBLIC KEY pem block type")
}
p, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
return nil, nil, fmt.Errorf("could not parse public key from block bytes: %s", err)
}
if p == nil {
return nil, nil, errors.New("returned public key was empty")
}
if publicKey, ok := p.(*rsa.PublicKey); ok {
return publicKey, pkeyID, nil
}
}
return nil, nil, errors.New("couldn't find public key")
}
// ExtractContent returns a string representation of the interface's Content property.
func ExtractContent(i WithContent) (string, error) {
contentProperty := i.GetActivityStreamsContent()
if contentProperty == nil {
return "", nil
}
for iter := contentProperty.Begin(); iter != contentProperty.End(); iter = iter.Next() {
if iter.IsXMLSchemaString() && iter.GetXMLSchemaString() != "" {
return iter.GetXMLSchemaString(), nil
}
}
return "", errors.New("no content found")
}
// ExtractAttachments returns a slice of attachments on the interface.
func ExtractAttachments(i WithAttachment) ([]*gtsmodel.MediaAttachment, error) {
attachments := []*gtsmodel.MediaAttachment{}
attachmentProp := i.GetActivityStreamsAttachment()
if attachmentProp == nil {
return attachments, nil
}
for iter := attachmentProp.Begin(); iter != attachmentProp.End(); iter = iter.Next() {
t := iter.GetType()
if t == nil {
continue
}
attachmentable, ok := t.(Attachmentable)
if !ok {
continue
}
attachment, err := ExtractAttachment(attachmentable)
if err != nil {
continue
}
attachments = append(attachments, attachment)
}
return attachments, nil
}
// ExtractAttachment returns a gts model of an attachment from an attachmentable interface.
func ExtractAttachment(i Attachmentable) (*gtsmodel.MediaAttachment, error) {
attachment := &gtsmodel.MediaAttachment{
File: gtsmodel.File{},
}
attachmentURL, err := ExtractURL(i)
if err != nil {
return nil, err
}
attachment.RemoteURL = attachmentURL.String()
mediaType := i.GetActivityStreamsMediaType()
if mediaType == nil || mediaType.Get() == "" {
return nil, errors.New("no media type")
}
attachment.File.ContentType = mediaType.Get()
attachment.Type = gtsmodel.FileTypeImage
name, err := ExtractName(i)
if err == nil {
attachment.Description = name
}
attachment.Blurhash = ExtractBlurhash(i)
attachment.Processing = gtsmodel.ProcessingStatusReceived
return attachment, nil
}
// ExtractBlurhash extracts the blurhash value (if present) from a WithBlurhash interface.
func ExtractBlurhash(i WithBlurhash) string {
if i.GetTootBlurhash() == nil {
return ""
}
return i.GetTootBlurhash().Get()
}
// ExtractHashtags returns a slice of tags on the interface.
func ExtractHashtags(i WithTag) ([]*gtsmodel.Tag, error) {
tags := []*gtsmodel.Tag{}
tagsProp := i.GetActivityStreamsTag()
if tagsProp == nil {
return tags, nil
}
for iter := tagsProp.Begin(); iter != tagsProp.End(); iter = iter.Next() {
t := iter.GetType()
if t == nil {
continue
}
if t.GetTypeName() != "Hashtag" {
continue
}
hashtaggable, ok := t.(Hashtaggable)
if !ok {
continue
}
tag, err := ExtractHashtag(hashtaggable)
if err != nil {
continue
}
tags = append(tags, tag)
}
return tags, nil
}
// ExtractHashtag returns a gtsmodel tag from a hashtaggable.
func ExtractHashtag(i Hashtaggable) (*gtsmodel.Tag, error) {
tag := &gtsmodel.Tag{}
hrefProp := i.GetActivityStreamsHref()
if hrefProp == nil || !hrefProp.IsIRI() {
return nil, errors.New("no href prop")
}
tag.URL = hrefProp.GetIRI().String()
name, err := ExtractName(i)
if err != nil {
return nil, err
}
tag.Name = strings.TrimPrefix(name, "#")
return tag, nil
}
// ExtractEmojis returns a slice of emojis on the interface.
func ExtractEmojis(i WithTag) ([]*gtsmodel.Emoji, error) {
emojis := []*gtsmodel.Emoji{}
tagsProp := i.GetActivityStreamsTag()
if tagsProp == nil {
return emojis, nil
}
for iter := tagsProp.Begin(); iter != tagsProp.End(); iter = iter.Next() {
t := iter.GetType()
if t == nil {
continue
}
if t.GetTypeName() != "Emoji" {
continue
}
emojiable, ok := t.(Emojiable)
if !ok {
continue
}
emoji, err := ExtractEmoji(emojiable)
if err != nil {
continue
}
emojis = append(emojis, emoji)
}
return emojis, nil
}
// ExtractEmoji ...
func ExtractEmoji(i Emojiable) (*gtsmodel.Emoji, error) {
emoji := &gtsmodel.Emoji{}
idProp := i.GetJSONLDId()
if idProp == nil || !idProp.IsIRI() {
return nil, errors.New("no id for emoji")
}
uri := idProp.GetIRI()
emoji.URI = uri.String()
emoji.Domain = uri.Host
name, err := ExtractName(i)
if err != nil {
return nil, err
}
emoji.Shortcode = strings.Trim(name, ":")
if i.GetActivityStreamsIcon() == nil {
return nil, errors.New("no icon for emoji")
}
imageURL, err := ExtractIconURL(i)
if err != nil {
return nil, errors.New("no url for emoji image")
}
emoji.ImageRemoteURL = imageURL.String()
return emoji, nil
}
// ExtractMentions extracts a slice of gtsmodel Mentions from a WithTag interface.
func ExtractMentions(i WithTag) ([]*gtsmodel.Mention, error) {
mentions := []*gtsmodel.Mention{}
tagsProp := i.GetActivityStreamsTag()
if tagsProp == nil {
return mentions, nil
}
for iter := tagsProp.Begin(); iter != tagsProp.End(); iter = iter.Next() {
t := iter.GetType()
if t == nil {
continue
}
if t.GetTypeName() != "Mention" {
continue
}
mentionable, ok := t.(Mentionable)
if !ok {
return nil, errors.New("mention was not convertable to ap.Mentionable")
}
mention, err := ExtractMention(mentionable)
if err != nil {
return nil, err
}
mentions = append(mentions, mention)
}
return mentions, nil
}
// ExtractMention extracts a gts model mention from a Mentionable.
func ExtractMention(i Mentionable) (*gtsmodel.Mention, error) {
mention := &gtsmodel.Mention{}
mentionString, err := ExtractName(i)
if err != nil {
return nil, err
}
// just make sure the mention string is valid so we can handle it properly later on...
_, _, err = util.ExtractMentionParts(mentionString)
if err != nil {
return nil, err
}
mention.NameString = mentionString
// the href prop should be the AP URI of a user we know, eg https://example.org/users/whatever_user
hrefProp := i.GetActivityStreamsHref()
if hrefProp == nil || !hrefProp.IsIRI() {
return nil, errors.New("no href prop")
}
mention.TargetAccountURI = hrefProp.GetIRI().String()
return mention, nil
}
// ExtractActor extracts the actor ID/IRI from an interface WithActor.
func ExtractActor(i WithActor) (*url.URL, error) {
actorProp := i.GetActivityStreamsActor()
if actorProp == nil {
return nil, errors.New("actor property was nil")
}
for iter := actorProp.Begin(); iter != actorProp.End(); iter = iter.Next() {
if iter.IsIRI() && iter.GetIRI() != nil {
return iter.GetIRI(), nil
}
}
return nil, errors.New("no iri found for actor prop")
}
// ExtractObject extracts a URL object from a WithObject interface.
func ExtractObject(i WithObject) (*url.URL, error) {
objectProp := i.GetActivityStreamsObject()
if objectProp == nil {
return nil, errors.New("object property was nil")
}
for iter := objectProp.Begin(); iter != objectProp.End(); iter = iter.Next() {
if iter.IsIRI() && iter.GetIRI() != nil {
return iter.GetIRI(), nil
}
}
return nil, errors.New("no iri found for object prop")
}
// ExtractVisibility extracts the gtsmodel.Visibility of a given addressable with a To and CC property.
//
// ActorFollowersURI is needed to check whether the visibility is FollowersOnly or not. The passed-in value
// should just be the string value representation of the followers URI of the actor who created the activity,
// eg https://example.org/users/whoever/followers.
func ExtractVisibility(addressable Addressable, actorFollowersURI string) (gtsmodel.Visibility, error) {
to, err := ExtractTos(addressable)
if err != nil {
return "", fmt.Errorf("deriveVisibility: error extracting TO values: %s", err)
}
cc, err := ExtractCCs(addressable)
if err != nil {
return "", fmt.Errorf("deriveVisibility: error extracting CC values: %s", err)
}
if len(to) == 0 && len(cc) == 0 {
return "", errors.New("deriveVisibility: message wasn't TO or CC anyone")
}
// for visibility derivation, we start by assuming most restrictive, and work our way to least restrictive
visibility := gtsmodel.VisibilityDirect
// if it's got followers in TO and it's not also CC'ed to public, it's followers only
if isFollowers(to, actorFollowersURI) {
visibility = gtsmodel.VisibilityFollowersOnly
}
// if it's CC'ed to public, it's unlocked
// mentioned SPECIFIC ACCOUNTS also get added to CC'es if it's not a direct message
if isPublic(cc) {
visibility = gtsmodel.VisibilityUnlocked
}
// if it's To public, it's just straight up public
if isPublic(to) {
visibility = gtsmodel.VisibilityPublic
}
return visibility, nil
}
// isPublic checks if at least one entry in the given uris slice equals
// the activitystreams public uri.
func isPublic(uris []*url.URL) bool {
for _, entry := range uris {
if strings.EqualFold(entry.String(), pub.PublicActivityPubIRI) {
return true
}
}
return false
}
// isFollowers checks if at least one entry in the given uris slice equals
// the given followersURI.
func isFollowers(uris []*url.URL, followersURI string) bool {
for _, entry := range uris {
if strings.EqualFold(entry.String(), followersURI) {
return true
}
}
return false
}
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// ExtractSensitive extracts whether or not an item is 'sensitive'.
// If no sensitive property is set on the item at all, or if this property
// isn't a boolean, then false will be returned by default.
func ExtractSensitive(withSensitive WithSensitive) bool {
sensitiveProp := withSensitive.GetActivityStreamsSensitive()
if sensitiveProp == nil {
return false
}
for iter := sensitiveProp.Begin(); iter != sensitiveProp.End(); iter = iter.Next() {
if iter.IsXMLSchemaBoolean() {
return iter.Get()
}
}
return false
}