const yaml = require('js-yaml'); const tpl = require('@tryghost/tpl'); const errors = require('@tryghost/errors'); const messages = { parsingError: { message: 'Could not parse provided YAML file: {context}.', help: 'Check provided file for typos and fix the named issues.', }, invalidYamlFormat: { message: 'YAML input cannot be a plain string. Check the format of your YAML file.', help: 'https://ghost.org/docs/themes/routing/' } }; /** * Takes a YAML formatted string and parses it and returns a JSON Object * @param {String} file the YAML file utf8 encoded * @returns {Object} parsed */ module.exports = function parseYaml(file) { try { const parsed = yaml.load(file); // yaml.load passes almost every yaml code. // Because of that, it's hard to detect if there's an error in the file. // But one of the obvious errors is the plain string output. // Here we check if the user made this mistake. if (typeof parsed === 'string') { throw new errors.IncorrectUsageError({ message: messages.invalidYamlFormat.message, help: messages.invalidYamlFormat.help }); } return parsed; } catch (error) { if (errors.utils.isIgnitionError(error)) { throw error; } // CASE: parsing failed, `js-yaml` tells us exactly what and where in the // `reason` property as well as in the message. // As the file uploaded is invalid, the person uploading must fix this - it's a 4xx error throw new errors.IncorrectUsageError({ message: tpl(messages.parsingError.message, {context: error.reason}), code: 'YAML_PARSER_ERROR', context: error.message, err: error, help: messages.parsingError.help }); } };