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Introducing Java Support in Socket
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@percy/core
Advanced tools
The core component of Percy's CLI and SDKs that handles creating builds, discovering snapshot assets, uploading snapshots, and finalizing builds. Uses `@percy/client` for API communication, a Puppeteer browser for asset discovery, and starts a local API s
@percy/core is a core library for Percy, a visual testing and review platform. It allows developers to capture screenshots of web pages and compare them to baseline images to detect visual changes. This package provides the core functionality needed to integrate Percy into various testing frameworks and CI/CD pipelines.
Initialize Percy
This code initializes a new instance of Percy, which is the first step in setting up visual testing for your project.
const Percy = require('@percy/core');
const percy = new Percy();
Capture a Snapshot
This code captures a snapshot of the specified URL. The snapshot is then compared to the baseline image to detect any visual changes.
await percy.snapshot('Home Page', { url: 'http://localhost:3000' });
Finalize Percy
This code finalizes the Percy session, uploading all captured snapshots for comparison and review.
await percy.finalize();
Cypress is a JavaScript end-to-end testing framework that also supports visual testing through plugins like cypress-image-snapshot. It provides a comprehensive testing solution but requires additional setup for visual testing.
Puppeteer is a Node library that provides a high-level API to control Chrome or Chromium over the DevTools Protocol. It can be used for visual testing by capturing screenshots and comparing them, but it lacks built-in visual comparison features.
WebdriverIO is a test automation framework that allows you to run tests based on the WebDriver protocol and Appium. It supports visual testing through plugins like wdio-visual-regression-service, but requires additional configuration.
The core component of Percy's CLI and SDKs that handles creating builds, discovering snapshot
assets, uploading snapshots, and finalizing builds. Uses @percy/client
for API communication, a
Puppeteer browser for asset discovery, and starts a local API server for posting snapshots from
other processes.
A Percy
class instance can manage a Percy build, take page snapshots, and perform snapshot asset
discovery. It also hosts a local API server for Percy SDKs to communicate with.
import Percy from '@percy/core'
// create a new instance
const percy = new Percy(percyOptions)
// create a new instance and start it
const percy = await Percy.start(percyOptions)
token
— Your project's PERCY_TOKEN
(default process.env.PERCY_TOKEN
)loglevel
— Logger level, one of "info"
, "warn"
, "error"
, "debug"
(default "info"
)server
— Controls whether an API server is created (default true
)port
— API server port (default 5338
)clientInfo
— Client info sent to Percy via a user-agent stringenvironmentInfo
— Environment info also sent with the user-agent stringdeferUploads
— Defer creating a build and uploading snapshots until laterThe following options can also be defined within a Percy config file
snapshot
— Snapshot options applied to each snapshot
widths
— Widths to take screenshots at (default [375, 1280]
)minHeight
— Minimum screenshot height (default 1024
)percyCSS
— Percy specific CSS to inject into the snapshotenableJavaScript
— Enable JavaScript for screenshots (default false
)discovery
— Asset discovery options
allowedHostnames
— Array of allowed hostnames to capture assets fromrequestHeaders
— Request headers used when discovering snapshot assetsauthorization
— Basic auth username
and password
for protected snapshot assetsdisableCache
— Disable asset caching (default false
)userAgent
— Custom user-agent string used when requesting assetscookies
— Browser cookies to use when requesting assetsnetworkIdleTimeout
— Milliseconds to wait for the network to idle (default 100
)concurrency
— Asset discovery concerrency (default 5
)launchOptions
— Asset discovery browser launch options
executable
— Browser executable path (default process.env.PERCY_BROWSER_EXECUTABLE
)timeout
— Discovery launch timeout, in milliseconds (default 30000
)args
— Additional browser process argumentsheadless
— Runs the browser headlessy (default true
)Additional Percy config file options are also allowed and will override any options defined by a local config file. These config file options are also made available to SDKs via the local API health check endpoint.
#start()
Starting a Percy
instance will start a local API server, start the asset discovery browser, and
create a new Percy build. If an asset discovery browser is not found, one will be downloaded.
await percy.start()
// [percy] Percy has started!
Starting a Percy
instance will start a local API server unless server
is false
. The server can
be found at http://localhost:5338/
or at the provided port
number.
/percy/healthcheck
– Responds with information about the running instance/percy/dom.js
– Responds with the @percy/dom
library/percy/idle
- Responds when the running instance is idle/percy/snapshot
– Calls #snapshot()
with provided snapshot options/percy/stop
- Remotely stops the running Percy
instance#stop([force])
Stopping a Percy
instance will wait for any pending snapshots, close the asset discovery browser,
close the local API server, and finalize the current Percy build. When uploads are deferred,
stopping the instance will also trigger processing of the upload queue. When force
is true
,
queues are cleared and closed to prevent queued snapshots from running.
await percy.stop()
// [percy] Processing 3 snapshots...
// [percy] Snapshot taken: Snapshot one
// [percy] Snapshot taken: Snapshot two
// [percy] Snapshot taken: Snapshot three
// [percy] Uploading 3 snapshots...
// [percy] Finalized build #1: https://percy.io/org/project/123
await percy.stop(true)
// [percy] Stopping percy...
// [percy] Finalized build #1: https://percy.io/org/project/123
#idle()
This method will resolve shortly after pending snapshots and uploads have completed and no more have started. Queued tasks are not considered pending unless they are actively running, so deferred uploads will not be awaited on with this method.
percy.snapshot(...);
percy.snapshot(...);
percy.snapshot(...);
await percy.idle()
// [percy] Snapshot taken: ...
// [percy] Snapshot taken: ...
// [percy] Snapshot taken: ...
#snapshot(options)
Performs asset discovery for a snapshot and queues uploading the snapshot to the associated Percy build. When an existing DOM snapshot is provided, it is served as the root resource during asset discovery. When no existing DOM snapshot is provided, a new one will be captured using any provided snapshot capture options.
// snapshots can be handled concurrently, no need to await
percy.snapshot({
name: 'Snapshot 1',
url: 'http://localhost:3000',
domSnapshot: domSnapshot,
clientInfo: 'my-sdk',
environmentInfo: 'my-lib'
...snapshotOptions
})
percy.snapshot({
name: 'Snapshot 2',
url: 'http://localhost:3000/',
...snapshotOptions,
// without a domSnapshot, capture options will be used to take one
waitForTimeout: 1000,
waitForSelector: '.done-loading',
execute: async () => {},
additionalSnapshots: [{
name: 'Snapshot 2.1',
execute: () => {},
...snapshotOptions
}]
})
url
— Snapshot URL (required)name
— Snapshot namedomSnapshot
— Snapshot DOM stringclientInfo
— Additional client infoenvironmentInfo
— Additional environment infodiscovery
- Limited snapshot specific discovery options
allowedHostnames
, requestHeaders
, authorization
, disableCache
, userAgent
Capture options can only be provided when domSnapshot
is missing.
waitForTimeout
— Milliseconds to wait before taking a snapshotwaitForSelector
— CSS selector to wait for before taking a snapshotexecute
— Function or function body to execute within the page before taking a snapshotadditionalSnapshots
— Array of additional sequential snapshots to take of the page
name
— Snapshot name (required if no prefix
or suffix
)prefix
— Snapshot name prefix (required if no name
or suffix
)suffix
— Snapshot name suffix (required if no name
or prefix
)waitForTimeout
, waitForSelector
, execute
— See aboveCommon snapshot options are also accepted and will override instance snapshot options. See instance options for common snapshot and discovery options.
By default, the browser is only downloaded when asset discovery is started for the first time. This is because many features of the CLI do not require a browser at all, and automatically downloading a browser creates a much heavier footprint than needed for those features. However, if your CI caches dependencies after the install step, the browser will not be cached and will be downloaded every time Percy runs without it.
If the environment variable PERCY_POSTINSTALL_BROWSER
is present and truthy, then the browser will
be downloaded after the package is installed to allow it to be cached. You can also require
@percy/core/post-install
within another node module to trigger the browser download manually.
If your CI comes with a Chromium binary pre-installed and you wish to skip Percy's own browser
installation, you can set the respective discovery.launchOptions.executable
config option. When
the executable at the provided path exists, the default download will be skipped and the provided
binary will be used instead. This option can also be set using the PERCY_BROWSER_EXECUTABLE
environment variable.
Warning! Percy is only tested against the browser it downloads automatically. When providing a custom browser executable, you may experience unexpected issues.
FAQs
The core component of Percy's CLI and SDKs that handles creating builds, discovering snapshot assets, uploading snapshots, and finalizing builds. Uses `@percy/client` for API communication, a Chromium browser for asset discovery, and starts a local API se
The npm package @percy/core receives a total of 350,061 weekly downloads. As such, @percy/core popularity was classified as popular.
We found that @percy/core demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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Product
We're excited to announce that Socket now supports the Java programming language.
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