bkp7 / fsnip

=====fsnip======

fsnip is a command line utility to extract and modify json from a file.

*/

const fs = require('fs')

const jp = require('jsonpath')

const stringify = require('json-stringify-pretty-compact')

const chalk = require('chalk')

export function cli (args) {

  if (args.length === 3 && args[2] === '--help') {

    console.info('fsnip is a tool for extracting json snippets from json files.\n\n' +

                 'Usage:\n' + '' +

                 'TODO still \n' +

                 '  fsnip FILE [options [arguments]]    process the file and output the result to the console\n' +

                 '  FILE         Specifies the file to process.\n' +

                 '  --ellipsify  replaces the passed object with ellipses (...)\n' +

                 '                 but excludes any keys which follow prepended by ~\n' +

                 '                 eg. fsnip myfile.json --ellipsify $..address ~postcode')

  } else if (args.length >= 3) {

    try {

      var txt = fs.readFileSync(args[2]).toString()

    } catch (err) {

      console.error(chalk.redBright("unable to read file '" + args[2] + "'"))

    }

    if (typeof txt !== 'undefined') {

      console.info(fsnipDo(args.slice(3), txt))

    }

  } else { // we couldn't recognise the format on the command line

    console.error(chalk.redBright('Unrecognised arguments passed to fsnip. See fsnip --help'))

  }

}

function fsnipDo (cmdOpts, inputText) {

  // does the processing of the fsnip command

  // inputText is the text we want to modify

  if (cmdOpts === null || cmdOpts.length === 0) { return inputText } // no processing required as no options passed in

  var src = { // a temporary structure containing the text we are working on its type eg. 'json' (which is set later)

    text: inputText,

    type: '',

    outputOptions: {},

    error: [],

    json: null,

    plain: null

  }

  // now we are going to parse through the options and arguments to extract individual options together with their arguments

  var cmdOpt = '' // current option from the cmdOptsString list

  var cmdArgs = [] // array containing any arguments for the cmdOpt

  for (var i = 0; i < cmdOpts.length; i++) {

    if (cmdOpts[i].substr(0, 2) === '--') { // this is a new option eg. --ellipsify

      processOption()

      cmdOpt = cmdOpts[i] // store the new option we have found

      cmdArgs = [] // reset ready for any new arguments

    } else {

      // this must be an argument for the current option

      if (cmdOpt === '') { // error if we don't currently have an option

        src.error.push("invalid argument '" + cmdOpts[i] + "' passed without valid option to fsnip")

      } else {

        cmdArgs.push(cmdOpts[i])

      }

    }

  }

  processOption()

  postProcess(src)

  return src.error.length === 0 ? src.text : chalk.redBright(src.error)

function runOption (option, args, inpObj) {

  // option is a string eg. '-jsonEllipsify'

  // arguments is an array of arguments for the option

  // inpObj is an object containing the text, type and json object we need to modify

  // this function acts as a marsheller to identify options and process them accordingly

  let funcs = {

    '--json': () => { json(inpObj) },

    '--prettify': () => { jsonPrettify(inpObj, args) },

    '--ellipsify': () => { jsonEllipsify(inpObj, args) },

    '--snip': () => { jsonSnippet(inpObj, args) },

    '--delKeys': () => { jsonDelKeys(inpObj, args) },

    '--from': () => { textFrom(inpObj, args, false) },

    '--start': () => { textFrom(inpObj, args, true) },

    '--to': () => { textTo(inpObj, args, false) },

    '--finish': () => { textTo(inpObj, args, true) }

  }

  if (funcs[option]) {

    funcs[option]()

  } else {

    inpObj.error.push("invalid option '" + option + "' for fsnip")

  }

}

function postProcess (inpObj) {

  // does any post process tidying up

  if (inpObj.type === 'json') {

    // stringify as required

    let opts = inpObj.outputOptions

    if (opts.maxLength === 'infinity' && opts.margins === false) {

      inpObj.text = JSON.stringify(inpObj.json)

    } else if (opts.maxLength === 0 && opts.margins === false) {

      inpObj.text = JSON.stringify(inpObj.json, null, opts.indent)

    } else {

      inpObj.text = stringify(inpObj.json, opts)

    }

    // now replace any placeholders. The placeholders are valid JSON but what we replace them with may not be valid JSON

    inpObj.text = inpObj.text.replace(/\[\s*"fsnipPlaceholderArrEllipses"\s*\]/g, '[...]')

    inpObj.text = inpObj.text.replace(/\{\s*"fsnipPlaceholderObj"\s*:\s*"Ellipses"\s*\}/g, '{...}') // do this separately to the one below so that if the object is empty it appears all on one line

    inpObj.text = inpObj.text.replace(/"fsnipPlaceholderObj"\s*:\s*"Ellipses"/g, '...')

    inpObj.text = inpObj.text.replace(/"fsnipPlaceholderStrEllipses"/g, '"..."')

  } else if (inpObj.type === 'plain') {

    inpObj.text = inpObj.plain.trim()

  }

}

export function setInputType (inpObj, newType) { // only exported for testing purposes

  if (typeof inpObj.type === 'undefined' || inpObj.type === '') { // type has not previously been set

    inpObj.type = newType

    if (newType === 'json') {

      inpObj.json = JSON.parse(inpObj.text)

      jsonPrettify(inpObj) // sets default output options for json

      return true

    } else if (newType === 'plain') {

      inpObj.plain = inpObj.text

      return true

    } else {

      return false

    }

  } else if (inpObj.type !== newType) { // it's already been set to something else so there's a problem

    if (typeof inpObj.error === 'undefined') { inpObj.error = [] }

    inpObj.error.push('cannot mix options designed to process different types of file')

    return false

  } else {

    return true

  }

}

function buildJsonSearchPath (keyName) {

  if (keyName.substr(0, 1) === '$') {

    return keyName

  } else {

    return "$..['" + keyName + "']"

  }

}

function removeQuotes (str) {

  // if the passed string has matching encapsulating quotes these are removed

  if ((str.substr(0, 1) === '\'' && str.substr(-1) === '\'') ||

      (str.substr(0, 1) === '"' && str.substr(-1) === '"')) {

    return str.substr(1, str.length - 2)

  } else {

    return str

  }

}

// =================json===============================

function json (inpObj) {

    // cmdArgs is an array of arguments

    // json is an object containing the json object we need to modify

  setInputType(inpObj, 'json') // all we do is flag our content as being json

}

// =================jsonPrettify=======================

function jsonPrettify (inpObj, cmdArgs) {

  // cmdArgs is an (optional) array of arguments being indent, maxLength, margins

  // they are all passed as strings so need to be converted to numbers where appropriate

  // we use - 0 to convert string numbers to numeric and === against itself to check for NaN

  if (setInputType(inpObj, 'json')) {

    let opts = inpObj.outputOptions

    // set defaults

    opts.margins = false

    opts.maxLength = 45

    opts.indent = 2

    // overwrite with any values passed in

    if (cmdArgs !== undefined) {

      if ((cmdArgs[0] - 0) === (cmdArgs[0] - 0)) { opts.indent = (cmdArgs[0] - 0) }

      if ((cmdArgs[1] - 0) === (cmdArgs[1] - 0)) { opts.maxLength = (cmdArgs[1] - 0) }

      if (cmdArgs[1] === 'infinity') { opts.maxLength = 'infinity' }

      opts.margins = (cmdArgs[2] === 'true') // defaults to false if margins anything other than true

    }

  }

}

// =================ellipsify==========================

function jsonEllipsify (inpObj, cmdArgs) {

  // cmdArgs is an array of arguments

  // json is an object containing the json object we need to modify

  if (setInputType(inpObj, 'json')) {

    // we have two types of argument for Ellipsify, plain and exclude so separate them out

    var cmdArgsPlain = []

    var cmdArgsExclude = []

    for (let i = 0; i < cmdArgs.length; i++) {

      if (cmdArgs[i].substr(0, 1) === '~') {

        cmdArgsExclude.push(removeQuotes(cmdArgs[i].substr(1)))

      } else {

        cmdArgsPlain.push(removeQuotes(cmdArgs[i]))

      }

    }

    if (cmdArgsPlain.length === 0) { cmdArgsPlain.push('$') }

    for (let i = 0; i < cmdArgsPlain.length; i++) {

      minimizeJsonProperty(inpObj.json, cmdArgsPlain[i], cmdArgsExclude)

    }

  }

}

export function minimizeJsonProperty (json, property, excludes) { // only exported for test purposes

  // this function takes a json object as input.and for every occurrence of the given property puts a placeholder

  // but only if it is an array or an object.

  var arrPlaceholder = ['fsnipPlaceholderArrEllipses'] // a valid json array used as a placeholder to be replaced later with [...] (which is not valid json)

  var strPlaceholder = 'fsnipPlaceholderStrEllipses'

  var jsonPaths = jp.paths(json, buildJsonSearchPath(property)) // creates an array of all the paths of instances of the the property we want to minimize

  for (var i = 0; i < jsonPaths.length; i++) {

    let jsonPath = jp.stringify(jsonPaths[i])

    switch (jp.value(json, jsonPath).constructor.name) {

      case 'Object':

        delKeys(json, jsonPath, excludes)

        jp.value(json, jsonPath)['fsnipPlaceholderObj'] = 'Ellipses' // add a placeholder for the Ellipses

        break

      case 'Array':

        jp.value(json, jsonPath, arrPlaceholder)

        break

      case 'String':

        jp.value(json, jsonPath, strPlaceholder)

        break

      default:

        // do nothing

    }

  }

  function delKeys (json, jsonPath, excludes) {

    var keys = Object.keys(jp.value(json, jsonPath))

    for (var j = 0; j < keys.length; j++) {

      if (excludes.indexOf(keys[j]) === -1) {

        // this key is not in the excludes list so we need to delete it

        delete jp.value(json, jsonPath)[keys[j]]

      }

    }

  }

}

// ===================snip Function==============================

function jsonSnippet (inpObj, cmdArgs) {

  // cmdArgs is an array of arguments

  // inpObj is an object containing the json object we need to modify

  // the format of the call is eg.

  // '--snip vessel 2' which would extract the second instance of "vessel" in the json supplied

  // with the instance identifier being optional

  if (setInputType(inpObj, 'json')) {

    var occ = 1

    if (cmdArgs.length === 1) {

      occ = 1 // by default we snip the first occurrence of this property

    } else if (cmdArgs.length === 2) {

      if ((cmdArgs[1] - 0) === (cmdArgs[1] - 0)) {

        occ = (cmdArgs[1] - 0)

        if (occ < 1) {

          inpObj.error.push('--snip requires its second argument to be a numeric values of at least 1 being the instance required')

          return

        }

      } else {

        inpObj.error.push("--snip requires its second argument to be numeric eg. '--snip vessel 2' with the optional second argument being the instance required")

        return

      }

    } else {

      inpObj.error.push("--snip requires 1 or 2 arguments eg. '--snip vessel 2' with the optional second argument being the instance required.")

      return

    }

    var jsonPaths = jp.paths(inpObj.json, buildJsonSearchPath(removeQuotes(cmdArgs[0]))) // creates an array of all the paths to this property

    if (jsonPaths.length < occ) {

      inpObj.error.push('--snip failed because there were only ' + jsonPaths.length + " occurrences of '" + removeQuotes(cmdArgs[0]) + "' found.")

      return

    }

    inpObj.json = jp.value(inpObj.json, jp.stringify(jsonPaths[occ - 1]))

  }

}

// ===================delKeys Function===========================

function jsonDelKeys (inpObj, cmdArgs) {

  // cmdArgs is an array of arguments

  // inpObj is an object containing the json object we need to remove keys from

  // the format of the call is eg.

  // '-jsonDelKeys vessel gnss' which would delete all instances of "vessel" and "gnss" in the json supplied

  if (setInputType(inpObj, 'json')) {

    for (var i = 0; i < cmdArgs.length; i++) {

      deleteJsonKey(inpObj.json, removeQuotes(cmdArgs[i]))

    }

  }

}

function deleteJsonKey (json, key) {

  // deletes all occurrences of key within json

  var jsonPaths = jp.paths(json, buildJsonSearchPath(key)) // creates an array of all the paths of instances of the key we want to delete

  var parent

  for (var i = 0; i < jsonPaths.length; i++) {

    let jsonPath = jp.stringify(jsonPaths[i])

    parent = jp.parent(json, jsonPath)

    if (Array.isArray(parent)) {

      parent.splice(jsonPaths[i][jsonPaths[i].length - 1], 1)

    } else {

      delete parent[jsonPaths[i][jsonPaths[i].length - 1]]

    }

  }

}

// ===================textFrom=================================

function textFrom (inpObj, cmdArgs, inclusive) {

  // cmdArgs is an array of arguments

  // inpObj is an object containing the text object we need to snip contents from

  // the format of the call is eg.

  // '--textFrom "some text" 2 - would start from the second instance of "some text"

  if (setInputType(inpObj, 'plain')) {

    let x = findLocation(inpObj, cmdArgs, inclusive ? '--start' : '--from')

    if (x.found) {

      inpObj.plain = inpObj.plain.substr(x.loc + (inclusive === true ? 0 : x.len))

    }

  }

}

// ===================textTo===================================

function textTo (inpObj, cmdArgs, inclusive) {

  // cmdArgs is an array of arguments

  // inpObj is an object containing the text object we need to snip contents from

  // the format of the call is eg.

  // '--textTo "some text" 2 - would go up to the second instance of "some text"

  if (setInputType(inpObj, 'plain')) {

    let x = findLocation(inpObj, cmdArgs, inclusive ? '--finish' : '--to')

    if (x.found) {

      inpObj.plain = inpObj.plain.substring(0, x.loc + (inclusive === true ? x.len : 0))

    }

  }

}

function findLocation (inpObj, cmdArgs, errString) {

  // find the location of the nth occurrence of the text specified in the command arguments

  let occ

  if (cmdArgs.length === 1) {

    occ = 1 // by default we take from the first occurrence of this text

  } else if (cmdArgs.length === 2) {

    if ((cmdArgs[1] - 0) === (cmdArgs[1] - 0)) {

      occ = (cmdArgs[1] - 0)

      if (occ < 1) {

        inpObj.error.push(errString + ' requires its second argument to be a numeric value of at least 1 being the instance required')

        return {found: false}

      }

    } else {

      inpObj.error.push(errString + " requires its second argument to be numeric eg. '" + errString + " sometext 2' with the optional second argument being the instance required")

      return {found: false}

    }

  } else {

    inpObj.error.push(errString + " requires 1 or 2 arguments eg. '" + errString + " sometext' with the optional second argument being the instance required.")

    return {found: false}

  }

  let x = -1

  let arg = removeQuotes(cmdArgs[0])

  for (let i = 0; i < occ; i++) {

    x = inpObj.plain.indexOf(arg, x + 1)

  }

  if (x === -1) {

    inpObj.error.push('unable to find occurrence ' + occ + ' of "' + arg + '"')

  }

  return {found: (x !== -1), loc: x, len: arg.length}

}