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📜  如何验证输入字段中的输入是否仅使用 express-validator 有字母?

📅  最后修改于: 2022-05-13 01:56:49.161000             🧑  作者: Mango

如何验证输入字段中的输入是否仅使用 express-validator 有字母?

在 HTML 表单中,我们经常需要验证不同的类型。验证现有电子邮件、验证密码长度、验证确认密码、验证以仅允许整数输入,这些是验证的一些示例。在某个输入字段中,只允许使用字母,即不允许任何数字或特殊字符。我们还可以使用 express-validator 中间件验证这些输入字段以仅接受字母。

安装 express-validator 的命令:

npm install express-validator

使用 express-validator 实现逻辑的步骤:

  • 安装 express-validator 中间件。
  • 创建一个validator.js 文件来编码所有的验证逻辑。
  • 通过 validateInputField: check(input field name) 验证输入并在验证 isAlpha() 上使用 ' 链接。 '
  • 使用路由中的验证名称(validateInputField)作为验证数组的中间件。
  • 从 express-validator 中解构 'validationResult'函数以使用它来查找任何错误。
  • 如果发生错误,则重定向到传递错误信息的同一页面。
  • 如果错误列表为空,则授予用户后续请求的访问权限。

注意:这里我们使用本地或自定义数据库来实现逻辑,可以按照相同的步骤在MongoDB或MySql等常规数据库中实现逻辑。

示例:此示例说明如何验证输入字段以仅允许使用字母。

文件名 - index.js

javascript
const express = require('express')
const bodyParser = require('body-parser')
const {validationResult} = require('express-validator')
const repo = require('./repository')
const { validateFirstName, validateLastName } = require('./validator')
const signupTemplet = require('./signup')
 
const app = express()
const port = process.env.PORT || 3000
 
// The body-parser middleware to parse form data
app.use(bodyParser.urlencoded({extended : true}))
 
// Get route to display HTML form to sign up
app.get('/signup', (req, res) => {
  res.send(signupTemplet({}))
})
 
// Post route to handle form submission logic and
app.post(
  '/signup',
  [validateFirstName, validateLastName],
  async (req, res) => {
    const errors = validationResult(req)
    if(!errors.isEmpty()){
      return res.send(signupTemplet({errors}))
    }
    const {email, fn, ln, password} = req.body
    await repo.create({
      email,
      'First Name':fn,
      'Last Name': ln,
      password
    })
    res.send('Sign Up successfully')
})
 
// Server setup
app.listen(port, () => {
  console.log(`Server start on port ${port}`)
})


javascript
// Importing node.js file system module
const fs = require('fs')
 
class Repository {
  constructor(filename) {
 
    // The filename where datas are going to store
    if(!filename) {
      throw new Error('Filename is required to create a datastore!')
    }
 
    this.filename = filename
 
    try {
      fs.accessSync(this.filename)
    } catch(err) {
 
      // If file not exist it is created with empty array
      fs.writeFileSync(this.filename, '[]')
    }
  }
 
  // Get all existing records
  async getAll(){
    return JSON.parse(
      await fs.promises.readFile(this.filename, {
        encoding : 'utf8'
      })
    )
  }
 
  // Create new record
  async create(attrs){
    const records = await this.getAll()
    records.push(attrs)
    await fs.promises.writeFile(
      this.filename,
      JSON.stringify(records, null, 2)  
    )
    return attrs
  }
}
 
// The 'datastore.json' file created at runtime
// and all the information provided via signup form
// store in this file in JSON format.
module.exports = new Repository('datastore.json')


javascript
const getError = (errors, prop) => {
  try {
    return errors.mapped()[prop].msg
  } catch (error) {
    return ''
  }
}
 
module.exports = ({errors}) => {
  return `
    
    
      
        
        
      
      
        
          
            
              

Sign Up

              
                             
                  
                                       
                                   
                
                  
                                       
                                     

${getError(errors, 'fn')}

                
                
                  
                                       
                                     

${getError(errors, 'ln')}

                
                
                  
                                       
                                   
                
                                   
              
            

          
        
                ` }


javascript
const {check} = require('express-validator')
const repo = require('./repository')
module.exports = {
   
  validateFirstName : check('fn')
    // To delete leading and trailing space
    .trim()
     
    // Validate the minimum length of the password
    // Optional for this context
    .isLength({min:3})
    // Custom message
    .withMessage('First Name must be 3 characters long')
 
    // Name must contains only alphabets
    .isAlpha()
    // Custom message
    .withMessage('First Name must be alphabetic'),
 
    validateLastName : check('ln')
    // To delete leading and trailing space
    .trim()
     
    // Validate the minimum length of the password
    // Optional for this context
    .isLength({min:2})
    // Custom message
    .withMessage('Last Name must be 2 characters long')
 
    // Name must contains only alphabets
    .isAlpha()
    // Custom message
    .withMessage('Last Name must be alphabetic')
}


文件名——repository.js:该文件包含创建本地数据库并与之交互的所有逻辑。

javascript

// Importing node.js file system module
const fs = require('fs')
 
class Repository {
  constructor(filename) {
 
    // The filename where datas are going to store
    if(!filename) {
      throw new Error('Filename is required to create a datastore!')
    }
 
    this.filename = filename
 
    try {
      fs.accessSync(this.filename)
    } catch(err) {
 
      // If file not exist it is created with empty array
      fs.writeFileSync(this.filename, '[]')
    }
  }
 
  // Get all existing records
  async getAll(){
    return JSON.parse(
      await fs.promises.readFile(this.filename, {
        encoding : 'utf8'
      })
    )
  }
 
  // Create new record
  async create(attrs){
    const records = await this.getAll()
    records.push(attrs)
    await fs.promises.writeFile(
      this.filename,
      JSON.stringify(records, null, 2)  
    )
    return attrs
  }
}
 
// The 'datastore.json' file created at runtime
// and all the information provided via signup form
// store in this file in JSON format.
module.exports = new Repository('datastore.json')

文件名 - signup.js:此文件包含显示注册表单的逻辑。

javascript

const getError = (errors, prop) => {
  try {
    return errors.mapped()[prop].msg
  } catch (error) {
    return ''
  }
}
 
module.exports = ({errors}) => {
  return `
    
    
      
        
        
      
      
        
          
            
              

Sign Up

              
                             
                  
                                       
                                   
                
                  
                                       
                                     

${getError(errors, 'fn')}

                
                
                  
                                       
                                     

${getError(errors, 'ln')}

                
                
                  
                                       
                                   
                
                                   
              
            

          
        
                ` }

文件名 - validator.js:此文件包含所有验证逻辑(验证输入字段以仅允许字母的逻辑)。

javascript

const {check} = require('express-validator')
const repo = require('./repository')
module.exports = {
   
  validateFirstName : check('fn')
    // To delete leading and trailing space
    .trim()
     
    // Validate the minimum length of the password
    // Optional for this context
    .isLength({min:3})
    // Custom message
    .withMessage('First Name must be 3 characters long')
 
    // Name must contains only alphabets
    .isAlpha()
    // Custom message
    .withMessage('First Name must be alphabetic'),
 
    validateLastName : check('ln')
    // To delete leading and trailing space
    .trim()
     
    // Validate the minimum length of the password
    // Optional for this context
    .isLength({min:2})
    // Custom message
    .withMessage('Last Name must be 2 characters long')
 
    // Name must contains only alphabets
    .isAlpha()
    // Custom message
    .withMessage('Last Name must be alphabetic')
}

文件名 - package.json

包.json 文件

输出:

当名字输入字段不只包含字母时尝试注册

尝试使用不只包含字母的输入字段“名字”注册时的响应

当名字和姓氏输入字段仅包含字母时尝试注册

尝试使用仅包含字母的输入字段“名字”、“姓氏”注册时的响应

注册成功后的数据库:

注册成功后的数据库

注意:我们在 signup.js 文件中使用了一些 Bulma 类(CSS 框架)来设计内容。