list()
Shortcut for listing entities from a Model. For complete control (pagination, start, end...) use the @google-cloud queries. When you configure a
list() shortcut query on a Schema, you can then later quickly fetch entities with pre-configured settings, like the order by or limit (those settings can be overridden later on).entitySchema.queries('list', options);The options object accepts the following "queries" properties
- limit
- order
- select
- ancestors
- filters (default operator is "=" and does not need to be passed)
- start
- offset
INFO: "order", "select" & "filters" can also be Arrays of settings (see example below).
Additional configuration The options accepts also the following properties
- namespace {string}
- readAll {boolean} true | false
- format {string} "JSON" | "ENTITY" (default: "JSON")
- showKey {boolean} true | false
- cache {boolean} true | false
- ttl {number | object}
- consistency {'strong' | 'eventual'}
namespace Overrides the default gstore instance namespace.
showKey (default: false)
Adds a "__key" property to the entity data with the complete Key information from the Datastore.
cache (default: the "global" cache configuration)
"true" = read from the cache and prime the cache with the query response.
ttl (default: the
cache.ttl.queries value) Custom TTL value for the cache. For multi-store it can be an object of TTL values.const options = {
...
namespace:'com.prod.myproject',
readAll: true,
format: "ENTITY",
showKey: true,
ttl: { memory: 60, redis: 600 }
};
consistency Specify either "strong" or "eventual". If not specified, default values are chosen by Datastore for the operation. Learn more about strong and eventual consistency here.
Example:
// blog-post.model.js
// Create Schema
const blogPostSchema = new gstore.Schema({
title : { type: String },
isDraft: { type: Boolean }
});
// List query settings
const listQueryOptions = {
limit : 10,
order : { property: 'title', descending: true }, // descending defaults to false and is optional
select : 'title',
ancestors : ['Parent', 123], // will add an "hasAncestor" filter
filters : ['isDraft', false] // operator defaults to "=" and is optional,
};
// Configure "list" shortcut Query
blogPostSchema.queries('list', listQueryOptions);
module.exports = gstore.model('BlogPost', blogPostSchema);
MyModel.list(options /*optional*/)@Returns: the response is an object with 2 properties:
- entities
- nextPageCursor // only present if there are more results to fetch
The nextPageCursor is for pagination and can be used in a future call to
MyModel.list({ start: pageCursor })Example:
const BlogPost = require('./blog-post.model');
BlogPost.list()
.then((response) => {
console.log(response.entities);
console.log(response.nextPageCursor); // only present if there are more results
});
// with a callback
BlogPost.list(function(err, response) {
if (err) {
// deal with err
}
console.log(response.entities);
console.log(response.nextPageCursor);
});
Example with Arrays of values (order, select, filters)
const listQueryOptions = {
order : [
{ property: 'title' },
{ property: 'createdOn', descending: true }
],
select : ['title', 'createdOn'],
filters : [['author', 'John Snow'], ['rating', '>', 4]]
};
blogPostSchema.queries('list', listQueryOptions);
The value of a filter can also be a function that returns a value. This function will be executed on each request. Useful for dynamic value for example when retrieving the current date.
Example
const listQuerySettings = {
filters : ['publishedOn', '<', () => new Date()],
};
...
BlogPost.list().then((response) => {
// --> will return all BlogPost with a publishedOn date previous from current date.
});
The global configuration set on the Schema can be overridden anytime by passing a new options object.
Model.list(options)const options = {
limit: 20,
start: 'somPageCursorFromPreviousQuery'
};
BlogPost.list(options)
.then((response) => { ... });
Last modified 4yr ago