indexDB entry to proficiency

Language 2023-09-09 20:18:05 views: null

Preface
Since models are often used in the development of 3D visualization projects, and a model is usually several meters or even dozens of meters in size, the loading speed is really slow for ordinary servers. In order to solve this loading speed problem, I thought of Several locally stored ones.

The first is cookies. Cookies definitely won’t work because they can only store up to 4k.

Secondly, localStorage can store up to 5m (not the size of one key, but the total size of all keys combined up to 5m), which is much larger than cookies. But when it comes to large models, it is still not enough. In actual development, most models are 10m-30m.

After searching for relevant information on the Internet, I learned about indexDB, and indexD is just right, because I found that my commonly used 3D framework three.js also uses indexDB for storage, and the storage size is more than 250m (depending on computer hardware and browser manufacturers) limits).

1. Directly upload the code to see the results more intuitively

Lazy people can just look at all the code for getting started.

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0">
  <title>Title</title>
  <link href="./favicon.png">
</head>
<body>
</body>
<script>
  let dbName = 'helloIndexDB', version = 1, storeName = 'helloStore'
 
  let indexedDB = window.indexedDB
  let db
  const request = indexedDB.open(dbName, version)
  request.onsuccess = function(event) {
    db = event.target.result // 数据库对象
    console.log('数据库打开成功')
  }
 
  request.onerror = function(event) {
    console.log('数据库打开报错')
  }
 
  request.onupgradeneeded = function(event) {
    // 数据库创建或升级的时候会触发
    console.log('onupgradeneeded')
    db = event.target.result // 数据库对象
    let objectStore
    if (!db.objectStoreNames.contains(storeName)) {
      objectStore = db.createObjectStore(storeName, { keyPath: 'id' }) // 创建表
      // objectStore.createIndex('name', 'name', { unique: true }) // 创建索引 可以让你搜索任意字段
    }
  }
 
 
  // 添加数据
  function addData(db, storeName, data) {
    let request = db.transaction([storeName], 'readwrite') // 事务对象 指定表格名称和操作模式（"只读"或"读写"）
      .objectStore(storeName) // 仓库对象
      .add(data)
 
    request.onsuccess = function(event) {
      console.log('数据写入成功')
    }
 
    request.onerror = function(event) {
      console.log('数据写入失败')
      throw new Error(event.target.error)
    }
  }
 
  // 根据id获取数据
  function getDataByKey(db, storeName, key) {
      let transaction = db.transaction([storeName]) // 事务
      let objectStore = transaction.objectStore(storeName) // 仓库对象
      let request = objectStore.get(key)
 
      request.onerror = function(event) {
        console.log('事务失败')
      }
 
      request.onsuccess = function(event) {
        console.log('主键查询结果: ', request.result)
      }
  }
 
  // 根据id修改数
  function updateDB(db, storeName, data) {
    let request = db.transaction([storeName], 'readwrite') // 事务对象
      .objectStore(storeName) // 仓库对象
      .put(data)
 
    request.onsuccess = function() {
      console.log('数据更新成功')
    }
 
    request.onerror = function() {
      console.log('数据更新失败')
    }
  }
 
  // 根据id删除数据
  function deleteDB(db, storeName, id) {
    let request = db.transaction([storeName], 'readwrite').objectStore(storeName).delete(id)
 
    request.onsuccess = function() {
      console.log('数据删除成功')
    }
 
    request.onerror = function() {
      console.log('数据删除失败')
    }
  }
 
  // 由于打开indexDB是异步的加个定时器避免 db对象还没获取到值导致 报错
  setTimeout(() => {
    addData(db, storeName, {
      id: new Date().getTime(), // 必须且值唯一
      name: '张三',
      age: 18,
      desc: 'helloWord'
    })
 
    getDataByKey(db, storeName, 1638160036008)
 
    updateDB(db, storeName, {id: 1638164880484, desc: '修改的内容'})
 
    deleteDB(db, storeName, 1638164870439)
  }, 1000)
 
</script>
</html>

Step one: Prepare the environment and basic html page

 basic html code

​<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0">
  <title>Title</title>
</head>
<body>
</body>
<script>
  
</script>
</html>

Step 2: Open the database (if it was not created automatically)

  let dbName = 'helloIndexDB', version = 1, storeName = 'helloStore'
 
  let indexedDB = window.indexedDB
  let db
  const request = indexedDB.open(dbName, version)
  request.onsuccess = function(event) {
    db = event.target.result // 数据库对象
    console.log('数据库打开成功')
  }
 
  request.onerror = function(event) {
    console.log('数据库打开报错')
  }
 
  request.onupgradeneeded = function(event) {
    // 数据库创建或升级的时候会触发
    console.log('onupgradeneeded')
    db = event.target.result // 数据库对象
    let objectStore
    if (!db.objectStoreNames.contains(storeName)) {
      objectStore = db.createObjectStore(storeName, { keyPath: 'id' }) // 创建表
      // objectStore.createIndex('name', 'name', { unique: true }) // 创建索引 可以让你搜索任意字段
    }
  }

After running the above code and opening the console, you can see the following effect. The database has been created, but there is no data at this time.

watermark,type_ZHJvaWRzYW5zZmFsbGJhY2s,shadow_50,text_Q1NETiBA5reL6Zuo5LiA55u06LWwfg==,size_19,color_FFFFFF,t_70,g_se,x_16

Step 3: Deposit a helloWorld 

  // 添加数据
  function addData(db, storeName, data) {
    let request = db.transaction([storeName], 'readwrite') // 事务对象 指定表格名称和操作模式（"只读"或"读写"）
      .objectStore(storeName) // 仓库对象
      .add(data)
 
    request.onsuccess = function(event) {
      console.log('数据写入成功')
    }
 
    request.onerror = function(event) {
      console.log('数据写入失败')
      throw new Error(event.target.error)
    }
  }
 
  // 由于打开indexDB是异步的加个定时器避免 db对象还没获取到值导致 报错
  setTimeout(() => {
    addData(db, storeName, {
      id: new Date().getTime(), // 必须且值唯一
      name: '张三',
      age: 18,
      desc: 'helloWord'
    })
  }, 1000)

After refreshing the page, you can see the following results. I have already saved it here (I refreshed it twice so there are two pieces of data)

watermark,type_ZHJvaWRzYW5zZmFsbGJhY2s,shadow_50,text_Q1NETiBA5reL6Zuo5LiA55u06LWwfg==,size_20,color_FFFFFF,t_70,g_se,x_16

 Step 4: Encapsulate delete, query, modify methods and execute them separately to view the results

 
  // 根据id获取数据
  function getDataByKey(db, storeName, key) {
      let transaction = db.transaction([storeName]) // 事务
      let objectStore = transaction.objectStore(storeName) // 仓库对象
      let request = objectStore.get(key)
 
      request.onerror = function(event) {
        console.log('事务失败')
      }
 
      request.onsuccess = function(event) {
        console.log('主键查询结果: ', request.result)
      }
  }
 
  // 根据id修改数
  function updateDB(db, storeName, data) {
    let request = db.transaction([storeName], 'readwrite') // 事务对象
      .objectStore(storeName) // 仓库对象
      .put(data)
 
    request.onsuccess = function() {
      console.log('数据更新成功')
    }
 
    request.onerror = function() {
      console.log('数据更新失败')
    }
  }
 
  // 根据id删除数据
  function deleteDB(db, storeName, id) {
    let request = db.transaction([storeName], 'readwrite').objectStore(storeName).delete(id)
 
    request.onsuccess = function() {
      console.log('数据删除成功')
    }
 
    request.onerror = function() {
      console.log('数据删除失败')
    }
  }
 
 
 
  // 由于打开indexDB是异步的加个定时器避免 db对象还没获取到值导致 报错
  setTimeout(() => {
    // addData(db, storeName, {
    //   id: new Date().getTime(), // 必须且值唯一
    //   name: '张三',
    //   age: 18,
    //   desc: 'helloWord'
    // })
 
    getDataByKey(db, storeName, 1638160036008)
 
    updateDB(db, storeName, {id: 1638164880484, desc: '修改的内容'})
 
    deleteDB(db, storeName, 1638164870439)
  }, 1000)

After executing the above code, the results on my side are as follows:

watermark,type_ZHJvaWRzYW5zZmFsbGJhY2s,shadow_50,text_Q1NETiBA5reL6Zuo5LiA55u06LWwfg==,size_20,color_FFFFFF,t_70,g_se,x_16

 2. Encapsulate the indexDB library,

Step 1: Encapsulate the class library

/**
 * 封装的方法以及用法
 * 打开数据库
 */
export function openDB(dbName, storeName, version = 1) {
  return new Promise((resolve, reject) => {
    let indexedDB = window.indexedDB
    let db
    const request = indexedDB.open(dbName, version)
    request.onsuccess = function(event) {
      db = event.target.result // 数据库对象
      resolve(db)
    }
 
    request.onerror = function(event) {
      reject(event)
    }
 
    request.onupgradeneeded = function(event) {
      // 数据库创建或升级的时候会触发
      console.log('onupgradeneeded')
      db = event.target.result // 数据库对象
      let objectStore
      if (!db.objectStoreNames.contains(storeName)) {
        objectStore = db.createObjectStore(storeName, { keyPath: 'id' }) // 创建表
        // objectStore.createIndex('name', 'name', { unique: true }) // 创建索引 可以让你搜索任意字段
      }
    }
  })
}
 
/**
 * 新增数据
 */
export function addData(db, storeName, data) {
  return new Promise((resolve, reject) => {
    let request = db.transaction([storeName], 'readwrite') // 事务对象 指定表格名称和操作模式（"只读"或"读写"）
      .objectStore(storeName) // 仓库对象
      .add(data)
 
    request.onsuccess = function(event) {
      resolve(event)
    }
 
    request.onerror = function(event) {
      throw new Error(event.target.error)
      reject(event)
    }
  })
}
 
/**
 * 通过主键读取数据
 */
export function getDataByKey(db, storeName, key) {
  return new Promise((resolve, reject) => {
    let transaction = db.transaction([storeName]) // 事务
    let objectStore = transaction.objectStore(storeName) // 仓库对象
    let request = objectStore.get(key)
 
    request.onerror = function(event) {
      reject(event)
    }
 
    request.onsuccess = function(event) {
      resolve(request.result)
    }
  })
}
 
/**
 * 通过游标读取数据
 */
export function cursorGetData(db, storeName) {
  let list = []
  let store = db.transaction(storeName, 'readwrite') // 事务
    .objectStore(storeName) // 仓库对象
  let request = store.openCursor() // 指针对象
  return new Promise((resolve, reject) => {
    request.onsuccess = function(e) {
      let cursor = e.target.result
      if (cursor) {
        // 必须要检查
        list.push(cursor.value)
        cursor.continue() // 遍历了存储对象中的所有内容
      } else {
        resolve(list)
      }
    }
    request.onerror = function(e) {
      reject(e)
    }
  })
}
 
/**
 * 通过索引读取数据
 */
export function getDataByIndex(db, storeName, indexName, indexValue) {
  let store = db.transaction(storeName, 'readwrite').objectStore(storeName)
  let request = store.index(indexName).get(indexValue)
  return new Promise((resolve, reject) => {
    request.onerror = function(e) {
      reject(e)
    }
    request.onsuccess = function(e) {
      resolve(e.target.result)
    }
  })
}
 
/**
 * 通过索引和游标查询记录
 */
export function cursorGetDataByIndex(db, storeName, indexName, indexValue) {
  let list = []
  let store = db.transaction(storeName, 'readwrite').objectStore(storeName) // 仓库对象
  let request = store.index(indexName) // 索引对象
    .openCursor(IDBKeyRange.only(indexValue)) // 指针对象
  return new Promise((resolve, reject) => {
    request.onsuccess = function(e) {
      let cursor = e.target.result
      if (cursor) {
        list.push(cursor.value)
        cursor.continue() // 遍历了存储对象中的所有内容
      } else {
        resolve(list)
      }
    }
    request.onerror = function(ev) {
      reject(ev)
    }
  })
}
 
/**
 * 更新数据
 */
export function updateDB(db, storeName, data) {
  let request = db.transaction([storeName], 'readwrite') // 事务对象
    .objectStore(storeName) // 仓库对象
    .put(data)
 
  return new Promise((resolve, reject) => {
    request.onsuccess = function(ev) {
      resolve(ev)
    }
 
    request.onerror = function(ev) {
      resolve(ev)
    }
  })
}
 
/**
 * 删除数据
 */
export function deleteDB(db, storeName, id) {
  let request = db.transaction([storeName], 'readwrite').objectStore(storeName).delete(id)
 
  return new Promise((resolve, reject) => {
    request.onsuccess = function(ev) {
      resolve(ev)
    }
 
    request.onerror = function(ev) {
      resolve(ev)
    }
  })
}
 
/**
 * 删除数据库
 */
export function deleteDBAll(dbName) {
  console.log(dbName)
  let deleteRequest = window.indexedDB.deleteDatabase(dbName)
  return new Promise((resolve, reject) => {
    deleteRequest.onerror = function(event) {
      console.log('删除失败')
    }
    deleteRequest.onsuccess = function(event) {
      console.log('删除成功')
    }
  })
}
 
/**
 * 关闭数据库
 */
export function closeDB(db) {
  db.close()
  console.log('数据库已关闭')
}
 
export default {
  openDB,
  addData,
  getDataByKey,
  cursorGetData,
  getDataByIndex,
  cursorGetDataByIndex,
  updateDB,
  deleteDB,
  deleteDBAll,
  closeDB
}

Step 2: Use the class library. How to use the library is as follows

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0">
  <title>Title</title>
  <link href="./favicon.png">
</head>
<body>
</body>
 
注意要加 type="module"
<script type="module">
-->
<script type="module">
  import IndexDB from './IndexDB.js'
 
  (async function() {
 
    const dbName = 'myDB', storeName = 'db_1'
    const db = await IndexDB.openDB(dbName, storeName, 1)
    var data = await IndexDB.addData(db, storeName, {
      id: 111, // 必须且值唯一
      name: '张三',
      age: 18,
      desc: 'helloWord'
    })
    console.log(data)
 
    var data = await IndexDB.getDataByKey(db, storeName, 111)
    console.log(data)
 
    var data = await IndexDB.updateDB(db, storeName, { id: 111, desc: '修改的内容' })
    console.log(data)
 
    var data = await IndexDB.deleteDB(db, storeName, 111)
    console.log(data)
  })()
</script>
</html>

3. Use the indexdb third-party class library indexdbwrapper (this method requires knowing how to use packaging tools for development but not knowing how to skip it)

/* 下载
 cnpm install --save indexdbwrapper
*/
// 引入
import IndexDBWrapper from 'indexdbwrapper'
// 使用
async function dbTest() {
      const dbName = 'dbName', storeName = 'storeName', version = 1
 
      const db = new IndexDBWrapper(dbName, version, {
        onupgradeneeded(event) {
          const db = event.target.result // 数据库对象
          let objectStore
          if (!db.objectStoreNames.contains(storeName)) {
            objectStore = db.createObjectStore(storeName, { keyPath: 'id' }) // 创建表
            // objectStore.createIndex('createTime', 'createTime', { unique: false }) // 创建索引 可以让你搜索任意字段
          }
        }
      })
      await db.open()
      await db.add(storeName, { id: new Date().getTime(), updateTime: new Date().getTime() })
      console.log(await db.get(storeName, 1639015754840))
      console.log(await db.put(storeName, { id: 1639015754840, put: 'put2' }))
      console.log(await db.get(storeName, 1639015754840))
      console.log(await db.delete(storeName, 1639015754840))
      // console.log(await db.clear(storeName))
}
dbTest()

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Origin blog.csdn.net/weixin_53841730/article/details/132431980
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