halfred/lib/resource.js

parses JSON HAL resources (Hypertext Application Language)

'use strict';

function Resource(links, curies, embedded, validationIssues) {
  var self = this;
  this._links = links || {};
  this._initCuries(curies);
  this._embedded = embedded || {};
  this._validation = validationIssues || [];
}

Resource.prototype._initCuries = function(curies) {
  this._curiesMap = {};
  if (!curies) {
    this._curies = [];
  } else {
    this._curies = curies;
    for (var i = 0; i < this._curies.length; i++) {
      var curie = this._curies[i];
      this._curiesMap[curie.name] = curie;
    }
  }
  this._preResolveCuries();
};

Resource.prototype._preResolveCuries = function() {
  this._resolvedCuriesMap = {};
  for (var i = 0; i < this._curies.length; i++) {
    var curie = this._curies[i];
    if (!curie.name) {
      continue;
    }
    for (var rel in this._links) {
      if (rel !== 'curies') {
        this._preResolveCurie(curie, rel);
      }
    }
  }
};

Resource.prototype._preResolveCurie = function(curie, rel) {
  var link = this._links[rel];
  var prefixAndReference = rel.split(/:(.+)/);
  var candidate = prefixAndReference[0];
  if (curie.name === candidate) {
    if (curie.templated && prefixAndReference.length >= 1) {
      // TODO resolving templated CURIES should use a small uri template
      // lib, not coded here ad hoc
      var href = curie.href.replace(/(.*){(.*)}(.*)/, '$1' +
          prefixAndReference[1] + '$3');
      this._resolvedCuriesMap[href] = rel;
    } else {
      this._resolvedCuriesMap[curie.href] = rel;
    }
  }
};

Resource.prototype.allLinkArrays = function() {
  return this._links;
};

Resource.prototype.linkArray = function(key) {
  return propertyArray(this._links, key);
};

Resource.prototype.link = function(key, index) {
  return elementOfPropertyArray(this._links, key, index);
};

Resource.prototype.hasCuries = function(key) {
  return this._curies.length > 0;
};

Resource.prototype.curieArray = function(key) {
  return this._curies;
};

Resource.prototype.curie = function(name) {
  return this._curiesMap[name];
};

Resource.prototype.reverseResolveCurie = function(fullUrl) {
  return this._resolvedCuriesMap[fullUrl];
};

Resource.prototype.allEmbeddedResourceArrays = function () {
  return this._embedded;
};

Resource.prototype.embeddedResourceArray = function(key) {
  return propertyArray(this._embedded, key);
};

Resource.prototype.embeddedResource = function(key, index) {
  return elementOfPropertyArray(this._embedded, key, index);
};

Resource.prototype.original = function() {
  return this._original;
};

function propertyArray(object, key) {
  return object != null ? object[key] : null;
}

function elementOfPropertyArray(object, key, index) {
  index = index || 0;
  var array = propertyArray(object, key);
  if (array != null && array.length >= 1) {
    return array[index];
  }
  return null;
}

Resource.prototype.validationIssues = function() {
  return this._validation;
};

// alias definitions
Resource.prototype.allLinks = Resource.prototype.allLinkArrays;
Resource.prototype.allEmbeddedArrays =
    Resource.prototype.allEmbeddedResources =
    Resource.prototype.allEmbeddedResourceArrays;
Resource.prototype.embeddedArray = Resource.prototype.embeddedResourceArray;
Resource.prototype.embedded = Resource.prototype.embeddedResource;
Resource.prototype.validation = Resource.prototype.validationIssues;

module.exports = Resource;