diff --git a/slader-legacy-backend/package.json b/slader-legacy-backend/package.json
new file mode 100644
index 0000000..ede9ddc
--- /dev/null
+++ b/slader-legacy-backend/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "slader-legacy-backend",
+  "version": "1.0.0",
+  "description": "",
+  "main": "src/index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "@types/better-sqlite3": "^5.4.3",
+    "@types/cors": "^2.8.12",
+    "@types/express": "^4.17.13",
+    "@types/node": "^16.4.8",
+    "better-sqlite3": "^7.4.3",
+    "cors": "^2.8.5",
+    "dotenv": "^10.0.0",
+    "express": "^4.17.1",
+    "express-async-handler": "^1.1.4",
+    "express-validator": "^6.12.1",
+    "reflect-metadata": "^0.1.13",
+    "ts-node": "^10.1.0",
+    "typedi": "^0.10.0",
+    "typescript": "^4.3.5"
+  }
+}
diff --git a/slader-legacy-backend/src/config.ts b/slader-legacy-backend/src/config.ts
new file mode 100644
index 0000000..988f83f
--- /dev/null
+++ b/slader-legacy-backend/src/config.ts
@@ -0,0 +1,5 @@
+require('dotenv').config()
+let appConfig = {
+    port: parseInt(process.env.SL_PORT as any)
+}
+export {appConfig}
diff --git a/slader-legacy-backend/src/entity-fill.ts b/slader-legacy-backend/src/entity-fill.ts
new file mode 100644
index 0000000..c1c4a8f
--- /dev/null
+++ b/slader-legacy-backend/src/entity-fill.ts
@@ -0,0 +1,27 @@
+import {IExercise, ITextbook, IToc} from "./types"
+
+export function fillIToc(single: any) {
+    return <IToc>{
+        section: single.section,
+        count: single.count,
+        pageBegin: single.pageBegin,
+        pageEnd: single.pageEnd
+    }
+}
+
+export function fillITextbook(single: any) {
+    return <ITextbook>{
+        title: single.title,
+        quantity: single.quantity
+    }
+}
+
+export function fillIExercise(single: any) {
+    return <IExercise>{
+        exercise: single.exercise,
+        section: single.section,
+        part: single.part,
+        page: single.page,
+        html: single.html
+    }
+}
diff --git a/slader-legacy-backend/src/includes.ts b/slader-legacy-backend/src/includes.ts
new file mode 100644
index 0000000..b9186ef
--- /dev/null
+++ b/slader-legacy-backend/src/includes.ts
@@ -0,0 +1,36 @@
+import {validationResult} from "express-validator"
+import {IResultJson} from "./types"
+import express from "express"
+import Database from "better-sqlite3"
+import path from "path"
+
+let db = Database(path.join(__dirname, '../slader.db'), {verbose: message => console.log('SQLITE3: ' + message)})
+
+export {db}
+export const resultJson = {
+    success(data: any) {
+        return <IResultJson>{
+            status: true,
+            data: data
+        }
+    },
+    error(data: any) {
+        return <IResultJson>{
+            status: false,
+            data: data
+        }
+    }
+}
+
+export function hasValidationErrors(req: express.Request, res: express.Response) {
+    let errors = validationResult(req)
+    if (!errors.isEmpty()) {
+        res.json(resultJson.error(errors.array()))
+        return true
+    }
+    return false
+}
+
+export function getTimestampInSeconds() {
+    return Math.floor(Date.now() / 1000)
+}
diff --git a/slader-legacy-backend/src/index.ts b/slader-legacy-backend/src/index.ts
new file mode 100644
index 0000000..06a7345
--- /dev/null
+++ b/slader-legacy-backend/src/index.ts
@@ -0,0 +1,13 @@
+import express from 'express'
+import cors from 'cors'
+import {textbookRouter} from "./routers/textbook-router"
+import {appConfig} from "./config"
+
+let app = express()
+app.use(cors())
+
+app.use('/textbook', textbookRouter)
+
+app.listen(appConfig.port, () => {
+    console.log('Server has started at port ' + appConfig.port)
+})
diff --git a/slader-legacy-backend/src/models/textbook-model.ts b/slader-legacy-backend/src/models/textbook-model.ts
new file mode 100644
index 0000000..2562e58
--- /dev/null
+++ b/slader-legacy-backend/src/models/textbook-model.ts
@@ -0,0 +1,65 @@
+import 'reflect-metadata'
+import {Service} from "typedi"
+import {db} from "../includes"
+import {fillIExercise, fillITextbook, fillIToc} from "../entity-fill"
+import {text} from "express"
+
+@Service()
+export class TextbookModel {
+    existTextbook(textbook: string) {
+        let raw = db.prepare('select rowid from solutions where textbook=? limit 1').get(textbook)
+        return !!raw?.rowid
+    }
+
+    existSection(textbook: string, section: string) {
+        let raw = db.prepare('select rowid from solutions where textbook=? and section=? limit 1').get(textbook, section)
+        return !!raw?.rowid
+    }
+
+    existExercise(textbook: string, section: string, exercise: string) {
+        let raw = db.prepare('select rowid from solutions ' +
+            'where textbook=? and section=? and exercise=? limit 1').get(textbook, section, exercise)
+        return !!raw?.rowid
+    }
+
+    getTextbooks() {
+        let raw = db.prepare('SELECT textbook as title,count(rowid) as quantity from solutions GROUP BY textbook').all()
+        return raw.map(value => fillITextbook(value))
+    }
+
+    findExercisesByTextbookSection(textbook: string, section: string) {
+        let raw = db.prepare('SELECT exercise,section,part,page,html ' +
+            'from solutions ' +
+            'where textbook=? ' +
+            'and section=? order by exercise asc').all(textbook, section)
+        return raw.map(value => fillIExercise(value))
+    }
+
+    findExercise(textbook: string, section: string, exercise: string) {
+        let raw = db.prepare('SELECT exercise,section,part,page,html ' +
+            'from solutions ' +
+            'where textbook=? ' +
+            'and section=? and exercise=?').get(textbook, section, exercise)
+        return fillIExercise(raw)
+    }
+
+    findExercisesByTextbookPage(textbook: string, page: number) {
+        let raw = db.prepare('SELECT exercise,section,part,page,html ' +
+            'from solutions ' +
+            'where textbook=? ' +
+            'and page=? order by exercise asc').all(textbook, page)
+        return raw.map(value => fillIExercise(value))
+    }
+
+    findTocByTextbook(textbook: string) {
+        let raw = db.prepare('SELECT section, ' +
+            'count(rowid) as count, ' +
+            'min(page) as pageBegin, ' +
+            'max(page) as pageEnd ' +
+            'FROM "solutions" ' +
+            'where textbook=? ' +
+            'group by section ' +
+            'order by pageBegin asc').all(textbook)
+        return raw.map(value => fillIToc(value))
+    }
+}
diff --git a/slader-legacy-backend/src/routers/textbook-router.ts b/slader-legacy-backend/src/routers/textbook-router.ts
new file mode 100644
index 0000000..1234831
--- /dev/null
+++ b/slader-legacy-backend/src/routers/textbook-router.ts
@@ -0,0 +1,53 @@
+import 'reflect-metadata'
+import express from "express"
+import {param, query} from "express-validator"
+import {Container} from "typedi"
+import {TextbookModel} from "../models/textbook-model"
+import expressAsyncHandler from "express-async-handler"
+import {TextbookService} from "../services/textbook-service"
+import {hasValidationErrors} from "../includes"
+
+let textbookRouter = express.Router()
+let textbookModel = Container.get(TextbookModel)
+let textbookService = Container.get(TextbookService)
+textbookRouter.get('/',
+    expressAsyncHandler(async (req: express.Request, res: express.Response) => {
+        res.json(await textbookService.listTextbooks())
+    })
+)
+textbookRouter.get('/:textbook/:section?/:exercise?',
+    param('textbook').notEmpty().bail().custom(input => {
+        if (!textbookModel.existTextbook(input)) {
+            throw new Error('textbook not exist')
+        }
+        return true
+    }),
+    query('page').optional().isInt({min: 1}),
+    param('section').optional().notEmpty().bail().custom((input, {req}) => {
+        if (!textbookModel.existSection(req.params!.textbook, input)) {
+            throw new Error('section not exist')
+        }
+        return true
+    }),
+    param('exercise').optional().notEmpty().bail().custom((input, {req}) => {
+        if (!textbookModel.existExercise(req.params!.textbook, req.params!.section, input)) {
+            throw new Error('exercise not exist')
+        }
+        return true
+    }),
+    expressAsyncHandler(async (req: express.Request, res: express.Response) => {
+        if (hasValidationErrors(req, res)) return
+        if (req.query.page) {
+            res.json(await textbookService.getPage(req.params.textbook, Number(req.query.page)))
+        } else if (req.params.exercise) {
+            res.json(await textbookService.getExercise(req.params.textbook, req.params.section, req.params.exercise))
+        } else if (req.params.section) {
+            res.json(await textbookService.getSection(req.params.textbook, req.params.section))
+        } else {
+            res.json(await textbookService.getTextbook(req.params.textbook))
+        }
+    })
+)
+
+
+export {textbookRouter}
diff --git a/slader-legacy-backend/src/services/textbook-service.ts b/slader-legacy-backend/src/services/textbook-service.ts
new file mode 100644
index 0000000..9730f1d
--- /dev/null
+++ b/slader-legacy-backend/src/services/textbook-service.ts
@@ -0,0 +1,30 @@
+import 'reflect-metadata'
+import {Inject, Service} from "typedi"
+import {TextbookModel} from "../models/textbook-model"
+import {resultJson} from "../includes"
+
+@Service()
+export class TextbookService {
+    @Inject()
+    textbookModel!: TextbookModel
+
+    async getTextbook(textbook: string) {
+        return resultJson.success(this.textbookModel.findTocByTextbook(textbook))
+    }
+
+    async getSection(textbook: string, section: string) {
+        return resultJson.success(this.textbookModel.findExercisesByTextbookSection(textbook, section))
+    }
+
+    async getExercise(textbook: string, section: string, exercise: string) {
+        return resultJson.success(this.textbookModel.findExercise(textbook, section, exercise))
+    }
+
+    async getPage(textbook: string, page: number) {
+        return resultJson.success(this.textbookModel.findExercisesByTextbookPage(textbook, page))
+    }
+
+    async listTextbooks() {
+        return resultJson.success(this.textbookModel.getTextbooks())
+    }
+}
diff --git a/slader-legacy-backend/src/types.ts b/slader-legacy-backend/src/types.ts
new file mode 100644
index 0000000..7b28fda
--- /dev/null
+++ b/slader-legacy-backend/src/types.ts
@@ -0,0 +1,24 @@
+export interface IResultJson {
+    status: boolean,
+    data: any
+}
+
+export interface IToc {
+    section: string,
+    count: number,
+    pageBegin: number,
+    pageEnd: number
+}
+
+export interface ITextbook {
+    title: string,
+    quantity: number
+}
+
+export interface IExercise {
+    exercise: string,
+    section: string,
+    part: string,
+    page: number,
+    html: string
+}
diff --git a/slader-legacy-backend/tsconfig.json b/slader-legacy-backend/tsconfig.json
new file mode 100644
index 0000000..7005dc5
--- /dev/null
+++ b/slader-legacy-backend/tsconfig.json
@@ -0,0 +1,86 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig.json to read more about this file */
+
+    /* Basic Options */
+    // "incremental": true,                         /* Enable incremental compilation */
+    "target": "ES2016",
+    /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
+    "module": "commonjs",
+    /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
+    // "lib": [],                                   /* Specify library files to be included in the compilation. */
+    "allowJs": true,
+    /* Allow javascript files to be compiled. */
+    // "checkJs": true,                             /* Report errors in .js files. */
+    // "jsx": "preserve",                           /* Specify JSX code generation: 'preserve', 'react-native', 'react', 'react-jsx' or 'react-jsxdev'. */
+    // "declaration": true,                         /* Generates corresponding '.d.ts' file. */
+    // "declarationMap": true,                      /* Generates a sourcemap for each corresponding '.d.ts' file. */
+    // "sourceMap": true,                           /* Generates corresponding '.map' file. */
+    // "outFile": "./",                             /* Concatenate and emit output to single file. */
+    "outDir": "./build",
+    /* Redirect output structure to the directory. */
+    "rootDir": "./src",
+    /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
+    // "composite": true,                           /* Enable project compilation */
+    // "tsBuildInfoFile": "./",                     /* Specify file to store incremental compilation information */
+    // "removeComments": true,                      /* Do not emit comments to output. */
+    // "noEmit": true,                              /* Do not emit outputs. */
+    // "importHelpers": true,                       /* Import emit helpers from 'tslib'. */
+    // "downlevelIteration": true,                  /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
+    // "isolatedModules": true,                     /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
+
+    /* Strict Type-Checking Options */
+    "strict": true,
+    /* Enable all strict type-checking options. */
+    // "noImplicitAny": true,                       /* Raise error on expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,                    /* Enable strict null checks. */
+    // "strictFunctionTypes": true,                 /* Enable strict checking of function types. */
+    // "strictBindCallApply": true,                 /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
+    // "strictPropertyInitialization": true,        /* Enable strict checking of property initialization in classes. */
+    // "noImplicitThis": true,                      /* Raise error on 'this' expressions with an implied 'any' type. */
+    // "alwaysStrict": true,                        /* Parse in strict mode and emit "use strict" for each source file. */
+
+    /* Additional Checks */
+    // "noUnusedLocals": true,                      /* Report errors on unused locals. */
+    // "noUnusedParameters": true,                  /* Report errors on unused parameters. */
+    // "noImplicitReturns": true,                   /* Report error when not all code paths in function return a value. */
+    // "noFallthroughCasesInSwitch": true,          /* Report errors for fallthrough cases in switch statement. */
+    // "noUncheckedIndexedAccess": true,            /* Include 'undefined' in index signature results */
+    // "noPropertyAccessFromIndexSignature": true,  /* Require undeclared properties from index signatures to use element accesses. */
+
+    /* Module Resolution Options */
+    // "moduleResolution": "node",                  /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
+    // "baseUrl": "./",                             /* Base directory to resolve non-absolute module names. */
+    // "paths": {},                                 /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
+    // "rootDirs": [],                              /* List of root folders whose combined content represents the structure of the project at runtime. */
+    "typeRoots": [
+      //      "./node_modules/**/*",
+      "./node_modules/@types"
+    ],
+    /* List of folders to include type definitions from. */
+    // "types": [],                                 /* Type declaration files to be included in compilation. */
+    // "allowSyntheticDefaultImports": true,        /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
+    "esModuleInterop": true,
+    /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    // "preserveSymlinks": true,                    /* Do not resolve the real path of symlinks. */
+    // "allowUmdGlobalAccess": true,                /* Allow accessing UMD globals from modules. */
+
+    /* Source Map Options */
+    // "sourceRoot": "",                            /* Specify the location where debugger should locate TypeScript files instead of source locations. */
+    // "mapRoot": "",                               /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSourceMap": true,                     /* Emit a single file with source maps instead of having a separate file. */
+    // "inlineSources": true,                       /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
+
+    /* Experimental Options */
+    "experimentalDecorators": true,
+    /* Enables experimental support for ES7 decorators. */
+    "emitDecoratorMetadata": true,
+    /* Enables experimental support for emitting type metadata for decorators. */
+
+    /* Advanced Options */
+    "skipLibCheck": true,
+    /* Skip type checking of declaration files. */
+    "forceConsistentCasingInFileNames": true
+    /* Disallow inconsistently-cased references to the same file. */
+  }
+}