Add adaptive media variants for weak networks

src/modules/posts/schemas/post.schema.ts

@@ -1,16 +1,32 @@
-import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
+import { Prop, Schema, SchemaFactory, raw } from '@nestjs/mongoose';
 import { HydratedDocument, Types } from 'mongoose';
 import { ModerationStatus } from '../../../common/enums/moderation-status.enum';
 import { PostType } from '../../../common/enums/post-type.enum';
 import { PostVisibility } from '../../../common/enums/post-visibility.enum';
 import {
   resolveManagedFileUrl,
+  resolveManagedFileUrlRecord,
+  resolveManagedFileUrlRecords,
   resolveManagedFileUrls,
 } from '../../../common/utils/public-url.util';
 import { User } from '../../users/schemas/user.schema';
 
 export type PostDocument = HydratedDocument<Post>;
 
+export type PostMediaVariantSet = {
+  originalUrl: string;
+  lowUrl: string;
+  mediumUrl: string;
+  highUrl: string;
+};
+
+const mediaVariantSetSchema = raw({
+  originalUrl: { type: String, default: '' },
+  lowUrl: { type: String, default: '' },
+  mediumUrl: { type: String, default: '' },
+  highUrl: { type: String, default: '' },
+});
+
 @Schema({ timestamps: true, versionKey: false })
 export class Post {
   @Prop({ type: Types.ObjectId, ref: User.name, required: true, index: true })
@@ -34,6 +50,9 @@ export class Post {
   @Prop({ default: '' })
   thumbnailUrl!: string;
 
+  @Prop({ type: mediaVariantSetSchema, default: null })
+  thumbnailVariants!: PostMediaVariantSet | null;
+
   @Prop({ default: '', trim: true, maxlength: 80 })
   style!: string;
 
@@ -49,6 +68,9 @@ export class Post {
   @Prop({ type: [String], default: [] })
   imageUrls!: string[];
 
+  @Prop({ type: [mediaVariantSetSchema], default: [] })
+  imageVariants!: PostMediaVariantSet[];
+
   @Prop({ type: [Types.ObjectId], ref: User.name, default: [], index: true })
   taggedUserIds!: Types.ObjectId[];
 
@@ -136,10 +158,12 @@ PostSchema.index({
 
 const transformManagedPostFiles = (_doc: unknown, ret: any) => {
   ret.imageUrls = resolveManagedFileUrls(ret.imageUrls);
+  ret.imageVariants = resolveManagedFileUrlRecords(ret.imageVariants);
   ret.videoUrl = resolveManagedFileUrl(ret.videoUrl);
   ret.hlsUrl = resolveManagedFileUrl(ret.hlsUrl);
   ret.audioUrl = resolveManagedFileUrl(ret.audioUrl);
   ret.thumbnailUrl = resolveManagedFileUrl(ret.thumbnailUrl);
+  ret.thumbnailVariants = resolveManagedFileUrlRecord(ret.thumbnailVariants);
   return ret;
 };