Ocelot-Social/backend/src/middleware/validation/validationMiddleware.js

import { UserInputError } from 'apollo-server'

const COMMENT_MIN_LENGTH = 1
const NO_POST_ERR_MESSAGE = 'Comment cannot be created without a post!'
const NO_CATEGORIES_ERR_MESSAGE =
  'You cannot save a post without at least one category or more than three'

const validateCreateComment = async (resolve, root, args, context, info) => {
  const content = args.content.replace(/<(?:.|\n)*?>/gm, '').trim()
  const { postId } = args

  if (!args.content || content.length < COMMENT_MIN_LENGTH) {
    throw new UserInputError(`Comment must be at least ${COMMENT_MIN_LENGTH} character long!`)
  }
  const session = context.driver.session()
  try {
    const postQueryRes = await session.run(
      `
    MATCH (post:Post {id: $postId})
    RETURN post`,
      {
        postId,
      },
    )
    const [post] = postQueryRes.records.map(record => {
      return record.get('post')
    })

    if (!post) {
      throw new UserInputError(NO_POST_ERR_MESSAGE)
    } else {
      return resolve(root, args, context, info)
    }
  } finally {
    session.close()
  }
}

const validateUpdateComment = async (resolve, root, args, context, info) => {
  const content = args.content.replace(/<(?:.|\n)*?>/gm, '').trim()
  if (!args.content || content.length < COMMENT_MIN_LENGTH) {
    throw new UserInputError(`Comment must be at least ${COMMENT_MIN_LENGTH} character long!`)
  }

  return resolve(root, args, context, info)
}

const validatePost = async (resolve, root, args, context, info) => {
  const { categoryIds } = args
  if (!Array.isArray(categoryIds) || !categoryIds.length || categoryIds.length > 3) {
    throw new UserInputError(NO_CATEGORIES_ERR_MESSAGE)
  }
  return resolve(root, args, context, info)
}

const validateUpdatePost = async (resolve, root, args, context, info) => {
  const { categoryIds } = args
  if (typeof categoryIds === 'undefined') return resolve(root, args, context, info)
  return validatePost(resolve, root, args, context, info)
}

const validateReport = async (resolve, root, args, context, info) => {
  const { resourceId } = args
  const { user, driver } = context
  if (resourceId === user.id) throw new Error('You cannot report yourself!')
  const session = driver.session()
  try {
    const reportQueryRes = await session.run(
      `
      MATCH (:User {id:$submitterId})-[:REPORTED]->(resource {id:$resourceId}) 
      RETURN labels(resource)[0] as label
    `,
      {
        resourceId,
        submitterId: user.id,
      },
    )
    const [existingReportedResource] = reportQueryRes.records.map(record => {
      return {
        label: record.get('label'),
      }
    })

    if (existingReportedResource) throw new Error(`${existingReportedResource.label}`)
    return resolve(root, args, context, info)
  } finally {
    session.close()
  }
}

export default {
  Mutation: {
    CreateComment: validateCreateComment,
    UpdateComment: validateUpdateComment,
    CreatePost: validatePost,
    UpdatePost: validateUpdatePost,
    report: validateReport,
  },
}