Add resource instance concept

Can now define resource classes bound to particular data points,
in particular they can be static data defined by app config and not
even in DB

1 files changed, 166 insertions, 12 deletions

diff --git a/app/node_modules/okresource/index.js b/app/node_modules/okresource/index.js
index 7cd51c7..0e99883 100644
--- a/app/node_modules/okresource/index.js
+++ b/app/node_modules/okresource/index.js
@@ -1,3 +1,4 @@
+var assign = require('object-assign');
 var Q = require('q');
 
 /**
@@ -31,15 +32,10 @@ function OKResource(options) {
 
   var type = options.type;
   this._db = options.db;
+  this._schema = schema;
 
   // Define properties which are part of the API
 
-  Object.defineProperty(this, 'schema', {
-    value: schema,
-    writable: false,
-    enumerable: true
-  });
-
   Object.defineProperty(this, 'spec', {
     value: schema.spec,
     writable: false,
@@ -57,13 +53,21 @@ function OKResource(options) {
     writable: false,
     enumerable: true
   });
+
+  // Whether this resource represents a specific data point
+  // or a whole class of data
+  Object.defineProperty(this, 'bound', {
+    value: false,
+    writable: false,
+    enumerable: true
+  });
 }
 
 /**
  * Throws an error if data does not conform to schema
  */
 OKResource.prototype.assertValid = function(data) {
-  this.schema.assertValid(data);
+  this._schema.assertValid(data);
 };
 
 OKResource.prototype.all = function() {
@@ -72,12 +76,14 @@ OKResource.prototype.all = function() {
 
 OKResource.prototype.create = function(data) {
   data = data || {};
+  var type = this.type;
+  var db = this._db;
   var id = data[this.idField];
   return Q.promise(function(resolve, reject) {
     if (!id) {
       reject(new Error('Data does not contain ID property'));
     } else {
-      this._db.create(this.type, data).then(resolve, reject);
+      db.create(type, data).then(resolve, reject);
     }
   });
 };
@@ -145,14 +151,14 @@ OKResource.prototype.updateOrCreate = function(data) {
   var type = this.type;
   var db = this._db;
   var idField = this.idField;
+  var query = {};
+  query[idField] = id;
   return Q.promise(function(resolve, reject) {
     if (!id) {
       reject(new Error('Cannot updateOrCreate without ID'));
     } else {
-      db.get(type, data.id).then(function(cached) {
-        var query = {};
-        query[idField] = id;
-        if (cached)
+      db.get(type, query).then(function(persisted) {
+        if (persisted)
           db.put(type, query, data).then(resolve, reject);
         else
           db.create(type, data).then(resolve, reject);
@@ -161,4 +167,152 @@ OKResource.prototype.updateOrCreate = function(data) {
   });
 };
 
+/**
+ * Create special resource which is bound to particular data point
+ * and has custom validation and query properties.
+ */
+OKResource.prototype.instance = function(options) {
+  return new OKResourceInstance(this, {
+    static: options.static
+  });
+};
+
+function OKResourceInstance(resource, options) {
+  if (!(this instanceof OKResourceInstance)) return new OKResourceInstance(options);
+  // Only support static data instances for now
+  if (!options.static)
+    throw new Error(
+      'Cannot create OKResourceInstance without static data');
+
+  // Resources with static data are a special case. They exist
+  // conceptually at all times since they are derived from app
+  // configuration, but may not actually be present
+  // in the database and need custom logic to handle this.
+  var staticData = assign({}, options.static);
+  var id = staticData[resource.idField];
+  if (!id)
+    throw new Error(
+        'Cannot create static OKResourceInstance without an ID field');
+
+  /**
+   * Ensure that static data is provided on get
+   */
+  this.get = function() {
+    return Q.promise(function(resolve, reject) {
+      resource.get(id).then(function(data) {
+        // Note the assign call. Don't expose private references!
+        if (data) {
+          resolve(assign({}, data, staticData));
+        } else {
+          resolve(assign({}, staticData));
+        }
+      }).fail(reject);
+    });
+  };
+
+  this.update = function(data) {
+    return Q.promise(function(resolve, reject) {
+      var valid = Object.keys(staticData).every(function(prop) {
+        return staticData[prop] === data[prop];
+      });
+      if (!valid) {
+        reject(new Error('Cannot update resource\'s static data'));
+      } else {
+        // When updating static resources, we create them if
+        // they don't actually exist in the DB
+        resource.updateOrCreate(data).then(resolve).fail(reject);
+      }
+    });
+  };
+
+  this.updateOrCreate = function(id) {
+    return Q.promise(function(resolve, reject) {
+      reject(new Error('Cannot updateOrCreate static resource'));
+    });
+  };
+
+  this.destroy = function(id) {
+    return Q.promise(function(resolve, reject) {
+      reject(new Error('Cannot destroy static resource'));
+    });
+  };
+
+  this.all = function(id) {
+    return Q.promise(function(resolve, reject) {
+      reject(new Error('Cannot get all for static resource'));
+    });
+  };
+
+  this.create = function(id) {
+    return Q.promise(function(resolve, reject) {
+      reject(new Error('Cannot create static resource'));
+    });
+  };
+
+  this.find = function(id) {
+    return Q.promise(function(resolve, reject) {
+      reject(new Error('Cannot perform find on static resource'));
+    });
+  };
+
+  this.assertValid = function(data) {
+    data = data || {};
+    Object.keys(staticData).forEach(function(prop) {
+      if (staticData[prop] !== data[prop]) {
+        // Validation error is in mschema error format
+        throw [{
+          property: prop,
+          constraint: 'static',
+          expected: staticData[prop],
+          actual: data[prop],
+          message: 'Data does not match static data'
+        }];
+      }
+    });
+    resource.assertValid(data);
+  };
+
+  Object.defineProperty(this, 'parent', {
+    value: resource,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'spec', {
+    value: resource.spec,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'id', {
+    value: id,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'type', {
+    value: resource.type,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'idField', {
+    value: resource.idField,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'bound', {
+    value: true,
+    writable: false,
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'class', {
+    value: resource,
+    writable: false,
+    enumerable: true
+  });
+}
+
 module.exports = OKResource;