Astro Runtime API
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Astro
global
Section titled Astro globalThe Astro
global is available in all contexts in .astro
files. It has the following functions:
Astro.glob()
Section titled Astro.glob()Use Vite’s import.meta.glob
to query project files.
Astro.glob('../pages/post/*.md')
can be replaced with:
Object.values(await import.meta.glob('../pages/post/*.md', { eager: true }));
See the imports guide for more information and usage.
Astro.glob()
is a way to load many local files into your static site setup.
.glob()
only takes one parameter: a relative URL glob of which local files you’d like to import. It’s asynchronous, and returns an array of the exports from matching files.
.glob()
can’t take variables or strings that interpolate them, as they aren’t statically analyzable. (See the imports guide for a workaround.) This is because Astro.glob()
is a wrapper of Vite’s import.meta.glob()
.
You can also use import.meta.glob()
itself in your Astro project. You may want to do this when:
- You need this feature in a file that isn’t
.astro
, like an API route.Astro.glob()
is only available in.astro
files, whileimport.meta.glob()
is available anywhere in the project. - You don’t want to load each file immediately.
import.meta.glob()
can return functions that import the file content, rather than returning the content itself. Note that this import includes all styles and scripts for any imported files. These will be bundled and added to the page whether or not a file is actually used, as this is decided by static analysis, not at runtime. - You want access to each file’s path.
import.meta.glob()
returns a map of a file’s path to its content, whileAstro.glob()
returns a list of content. - You want to pass multiple patterns; for example, you want to add a “negative pattern” that filters out certain files.
import.meta.glob()
can optionally take an array of glob strings, rather than a single string.
Read more in the Vite documentation.
Markdown Files
Section titled Markdown FilesMarkdown files loaded with Astro.glob()
return the following MarkdownInstance
interface:
You can optionally provide a type for the frontmatter
variable using a TypeScript generic.
Astro Files
Section titled Astro FilesAstro files have the following interface:
Other Files
Section titled Other FilesOther files may have various different interfaces, but Astro.glob()
accepts a TypeScript generic if you know exactly what an unrecognized file type contains.
Astro.props
Section titled Astro.propsAstro.props
is an object containing any values that have been passed as component attributes. Layout components for .md
and .mdx
files receive frontmatter values as props.
Astro.params
Section titled Astro.paramsAstro.params
is an object containing the values of dynamic route segments matched for this request.
In static builds, this will be the params
returned by getStaticPaths()
used for prerendering dynamic routes.
In SSR builds, this can be any value matching the path segments in the dynamic route pattern.
See also: params
Astro.request
Section titled Astro.requestType: Request
Astro.request
is a standard Request object. It can be used to get the url
, headers
, method
, and even body of the request.
See also: Astro.url
With the default output: 'static'
option, Astro.request.url
does not contain search parameters, like ?foo=bar
, as it’s not possible to determine them ahead of time during static builds. However in output: 'server'
mode, Astro.request.url
does contain search parameters as it can be determined from a server request.
Astro.response
Section titled Astro.responseType: ResponseInit & { readonly headers: Headers }
Astro.response
is a standard ResponseInit
object. It has the following structure.
status
: The numeric status code of the response, e.g.,200
.statusText
: The status message associated with the status code, e.g.,'OK'
.headers
: AHeaders
instance that you can use to set the HTTP headers of the response.
Astro.response
is used to set the status
, statusText
, and headers
for a page’s response.
Or to set a header:
Astro.cookies
Section titled Astro.cookiesType: AstroCookies
astro@1.4.0
Astro.cookies
contains utilities for reading and manipulating cookies in server-side rendering mode.
Type: (key: string, options?: AstroCookieGetOptions) => AstroCookie | undefined
Gets the cookie as an AstroCookie
object, which contains the value
and utility functions for converting the cookie to non-string types.
Type: (key: string, options?: AstroCookieGetOptions) => boolean
Whether this cookie exists. If the cookie has been set via Astro.cookies.set()
this will return true, otherwise it will check cookies in the Astro.request
.
Type: (key: string, value: string | object, options?: AstroCookieSetOptions) => void
Sets the cookie key
to the given value. This will attempt to convert the cookie value to a string. Options provide ways to set cookie features, such as the maxAge
or httpOnly
.
delete
Section titled deleteType: (key: string, options?: AstroCookieDeleteOptions) => void
Invalidates a cookie by setting the expiration date in the past (0 in Unix time).
Once a cookie is “deleted” (expired), Astro.cookies.has()
will return false
and Astro.cookies.get()
will return an AstroCookie
with a value
of undefined
. Options available when deleting a cookie are: domain
, path
, httpOnly
, sameSite
, and secure
.
merge
Section titled mergeType: (cookies: AstroCookies) => void
Merges a new AstroCookies
instance into the current instance. Any new cookies will be added to the current instance and any cookies with the same name will overwrite existing values.
headers
Section titled headersType: () => Iterator<string>
Gets the header values for Set-Cookie
that will be sent out with the response.
AstroCookie
Section titled AstroCookieGetting a cookie via Astro.cookies.get()
returns a AstroCookie
type. It has the following structure.
value
Section titled valueType: string
The raw string value of the cookie.
Type: () => Record<string, any>
Parses the cookie value via JSON.parse()
, returning an object. Throws if the cookie value is not valid JSON.
number
Section titled numberType: () => number
Parses the cookie value as a Number. Returns NaN if not a valid number.
boolean
Section titled booleanType: () => boolean
Converts the cookie value to a boolean.
AstroCookieGetOptions
Section titled AstroCookieGetOptions
追加:
astro@4.1.0
Getting a cookie also allows specifying options via the AstroCookieGetOptions
interface:
decode
Section titled decodeType: (value: string) => string
Allows customization of how a cookie is deserialized into a value.
AstroCookieSetOptions
Section titled AstroCookieSetOptions
追加:
astro@4.1.0
Setting a cookie via Astro.cookies.set()
allows passing in a AstroCookieSetOptions
to customize how the cookie is serialized.
domain
Section titled domainType: string
Specifies the domain. If no domain is set, most clients will interpret to apply to the current domain.
expires
Section titled expiresType: Date
Specifies the date on which the cookie will expire.
httpOnly
Section titled httpOnlyType: boolean
If true, the cookie will not be accessible client-side.
maxAge
Section titled maxAgeType: number
Specifies a number, in seconds, for which the cookie is valid.
Type: string
Specifies a subpath of the domain in which the cookie is applied.
sameSite
Section titled sameSiteType: boolean | 'lax' | 'none' | 'strict'
Specifies the value of the SameSite cookie header.
secure
Section titled secureType: boolean
If true, the cookie is only set on https sites.
encode
Section titled encodeType: (value: string) => string
Allows customizing how the cookie is serialized.
Astro.redirect()
Section titled Astro.redirect()Type: (path: string, status?: number) => Response
Allows you to redirect to another page, and optionally provide an HTTP response status code as a second parameter.
A page (and not a child component) must return
the result of Astro.redirect()
for the redirect to occur.
For statically-generated sites, this will produce a client redirect using a <meta http-equiv="refresh">
tag and does not support status codes.
When using an on-demand rendering mode, status codes are supported. Astro will serve redirected requests with a default HTTP response status of 302
unless another code is specified.
The following example redirects a user to a login page:
Astro.rewrite()
Section titled Astro.rewrite()Type: (rewritePayload: string | URL | Request) => Promise<Response>
astro@4.13.0
Allows you to serve content from a different URL or path without redirecting the browser to a new page.
The method accepts either a string, a URL
, or a Request
for the location of the path.
Use a string to provide an explicit path:
Use a URL
type when you need to construct the URL path for the rewrite. The following example renders a page’s parent path by creating a new URL from the relative "../"
path:
Use a Request
type for complete control of the Request
sent to the server for the new path. The following example sends a request to render the parent page while also providing headers:
Astro.url
Section titled Astro.urlType: URL
astro@1.0.0-rc
A URL object constructed from the current Astro.request.url
URL string value. Useful for interacting with individual properties of the request URL, like pathname and origin.
Equivalent to doing new URL(Astro.request.url)
.
Astro.url
will be localhost
in dev mode if site is not configured for static sites, and for on-demand rendered routes.
You can also use Astro.url
to create new URLs by passing it as an argument to new URL()
.
Astro.clientAddress
Section titled Astro.clientAddressType: string
astro@1.0.0-rc
Specifies the IP address of the request. This property is only available when building for SSR (server-side rendering) and should not be used for static sites.
Astro.site
Section titled Astro.siteType: URL | undefined
Astro.site
returns a URL
made from site
in your Astro config. If site
in your Astro config isn’t defined, Astro.site
won’t be defined.
Astro.generator
Section titled Astro.generatorType: string
astro@1.0.0
Astro.generator
is a convenient way to add a <meta name="generator">
tag with your current version of Astro. It follows the format "Astro v1.x.x"
.
Astro.slots
Section titled Astro.slotsAstro.slots
contains utility functions for modifying an Astro component’s slotted children.
Astro.slots.has()
Section titled Astro.slots.has()Type: (slotName: string) => boolean
You can check whether content for a specific slot name exists with Astro.slots.has()
. This can be useful when you want to wrap slot contents, but only want to render the wrapper elements when the slot is being used.
Astro.slots.render()
Section titled Astro.slots.render()Type: (slotName: string, args?: any[]) => Promise<string>
You can asynchronously render the contents of a slot to a string of HTML using Astro.slots.render()
.
This is for advanced use cases! In most circumstances, it is simpler to render slot contents with the <slot />
element.
Astro.slots.render()
optionally accepts a second argument: an array of parameters that will be forwarded to any function children. This can be useful for custom utility components.
For example, this <Shout />
component converts its message
prop to uppercase and passes it to the default slot:
A callback function passed as <Shout />
’s child will receive the all-caps message
parameter:
Callback functions can be passed to named slots inside a wrapping HTML element tag with a slot
attribute. This element is only used to transfer the callback to a named slot and will not be rendered onto the page.
Use a standard HTML element for the wrapping tag, or any lower case tag (e.g. <fragment>
instead of <Fragment />
) that will not be interpreted as a component. Do not use the HTML <slot>
element as this will be interpreted as an Astro slot.
Astro.self
Section titled Astro.selfAstro.self
allows Astro components to be recursively called. This behaviour lets you render an Astro component from within itself by using <Astro.self>
in the component template. This can be helpful for iterating over large data stores and nested data-structures.
This component could then be used like this:
And would render HTML like this:
Astro.locals
Section titled Astro.locals
追加:
astro@2.4.0
Astro.locals
is an object containing any values from the context.locals
object from a middleware. Use this to access data returned by middleware in your .astro
files.
Astro.preferredLocale
Section titled Astro.preferredLocaleType: string | undefined
astro@3.5.0
Astro.preferredLocale
is a computed value that represents the preferred locale of the user.
It is computed by checking the configured locales in your i18n.locales
array and locales supported by the users’s browser via the header Accept-Language
. This value is undefined
if no such match exists.
This property is only available when building for SSR (server-side rendering) and should not be used for static sites.
Astro.preferredLocaleList
Section titled Astro.preferredLocaleListType: string[] | undefined
astro@3.5.0
Astro.preferredLocaleList
represents the array of all locales that are both requested by the browser and supported by your website. This produces a list of all compatible languages between your site and your visitor.
If none of the browser’s requested languages are found in your locales array, then the value is []
: you do not support any of your visitor’s preferred locales.
If the browser does not specify any preferred languages, then this value will be i18n.locales
: all of your supported locales will be considered equally preferred by a visitor with no preferences.
This property is only available when building for SSR (server-side rendering) and should not be used for static sites.
Astro.currentLocale
Section titled Astro.currentLocaleType: string | undefined
astro@3.5.6
The locale computed from the current URL, using the syntax specified in your locales
configuration. If the URL does not contain a /[locale]/
prefix, then the value will default to i18n.defaultLocale
.
Astro.getActionResult()
Section titled Astro.getActionResult()Type: (action: TAction) => ActionReturnType<TAction> | undefined
astro@4.15.0
Astro.getActionResult()
is a function that returns the result of an Action submission. This accepts an action function as an argument (e.g. actions.logout
) and returns a data
or error
object when a submission is received. Otherwise, it will return undefined
.
Astro.callAction()
Section titled Astro.callAction()
追加:
astro@4.15.0
Astro.callAction()
is a function used to call an Action handler directly from your Astro component. This function accepts an Action function as the first argument (e.g. actions.logout
) and any input that action receives as the second argument. It returns the result of the action as a promise.
Astro.routePattern
Section titled Astro.routePatternType: string
astro@5.0.0
ベータ
The route pattern responsible for generating the current page or route. In file-based routing, this resembles the file path in your project used to create the route. When integrations create routes for your project, context.routePattern
is identical to the value for injectRoute.pattern
.
The value will start with a leading slash and look similar to the path of a page component relative to your srcDir/pages/
folder without a file extension.
For example, the file src/pages/en/blog/[slug].astro
will return /en/blog/[slug]
for context.routePattern
. Every page on your site generated by that file (e.g. /en/blog/post-1/
, /en/blog/post-2/
, etc.) shares the same value for context.routePattern
. In the case of index.*
routes, the route pattern will not include the word “index.” For example, src/pages/index.astro
will return /
.
You can use this property to understand which route is rendering your component. This allows you to target or analyze similarly-generated page URLs together. For example, you can use it to conditionally render certain information, or collect metrics about which routes are slower.
See also: context.routePattern
Astro.isPrerendered
Section titled Astro.isPrerenderedType: boolean
astro@5.0.0
ベータ
A boolean representing whether or not the current page is prerendered.
You can use this property to run conditional logic in middleware, for example, to avoid accessing headers in prerendered pages.
See also: context.isPrerendered
Endpoint Context
Section titled Endpoint ContextEndpoint functions receive a context object as the first parameter. It mirrors many of the Astro
global properties.
context.params
Section titled context.paramscontext.params
is an object containing the values of dynamic route segments matched for this request.
In static builds, this will be the params
returned by getStaticPaths()
used for prerendering dynamic routes.
In SSR builds, this can be any value matching the path segments in the dynamic route pattern.
See also: params
context.props
Section titled context.props
追加:
astro@1.5.0
context.props
is an object containing any props
passed from getStaticPaths()
. Because getStaticPaths()
is not used when building for SSR (server-side rendering), context.props
is only available in static builds.
See also: Data Passing with props
context.request
Section titled context.requestType: Request
A standard Request object. It can be used to get the url
, headers
, method
, and even body of the request.
See also: Astro.request
context.cookies
Section titled context.cookiesType: AstroCookies
context.cookies
contains utilities for reading and manipulating cookies.
See also: Astro.cookies
context.url
Section titled context.urlType: URL
astro@1.5.0
A URL object constructed from the current context.request.url
URL string value.
See also: Astro.url
context.clientAddress
Section titled context.clientAddressType: string
astro@1.5.0
Specifies the IP address of the request. This property is only available when building for SSR (server-side rendering) and should not be used for static sites.
See also: Astro.clientAddress
context.site
Section titled context.siteType: URL | undefined
astro@1.5.0
context.site
returns a URL
made from site
in your Astro config. If undefined, this will return a URL generated from localhost
.
See also: Astro.site
context.generator
Section titled context.generatorType: string
astro@1.5.0
context.generator
is a convenient way to indicate the version of Astro your project is running. It follows the format "Astro v1.x.x"
.
See also: Astro.generator
context.redirect()
Section titled context.redirect()Type: (path: string, status?: number) => Response
astro@1.5.0
context.redirect()
returns a Response object that allows you to redirect to another page. This function is only available when building for SSR (server-side rendering) and should not be used for static sites.
See also: Astro.redirect()
context.rewrite()
Section titled context.rewrite()Type: (rewritePayload: string | URL | Request) => Promise<Response>
astro@4.13.0
Allows you to serve content from a different URL or path without redirecting the browser to a new page.
The method accepts either a string, a URL
, or a Request
for the location of the path.
Use a string to provide an explicit path:
Use a URL
type when you need to construct the URL path for the rewrite. The following example renders a page’s parent path by creating a new URL from the relative "../"
path:
Use a Request
type for complete control of the Request
sent to the server for the new path. The following example sends a request to render the parent page while also providing headers:
See also: Astro.rewrite()
context.locals
Section titled context.locals
追加:
astro@2.4.0
context.locals
is an object used to store and access arbitrary information during the lifecycle of a request.
Middleware functions can read and write the values of context.locals
:
API endpoints can only read information from context.locals
:
The value of locals
cannot be overridden at run time. Doing so would risk wiping out all the information stored by the user. Astro performs checks and will throw an error if locals
are overridden.
See also: Astro.locals
context.getActionResult()
Section titled context.getActionResult()Type: (action: TAction) => ActionReturnType<TAction> | undefined
astro@4.15.0
context.getActionResult()
is a function that returns the result of an Action submission. This accepts an action function as an argument (e.g. actions.logout
), and returns a data
or error
object when a submission is received. Otherwise, it will return undefined
.
See also Astro.getActionResult()
context.callAction()
Section titled context.callAction()
追加:
astro@4.15.0
context.callAction()
is a function used to call an Action handler directly from your Astro component. This function accepts an Action function as the first argument (e.g. actions.logout
) and any input that action receives as the second argument. It returns the result of the action as a promise.
See also Astro.callAction()
context.routePattern
Section titled context.routePatternType: string
astro@5.0.0
ベータ
The route pattern responsible for generating the current page or route. In file-based routing, this resembles the file path in your project used to create the route. When integrations create routes for your project, context.routePattern
is identical to the value for injectRoute.pattern
.
The value will start with a leading slash and look similar to the path of a page component relative to your srcDir/pages/
folder without a file extension.
For example, the file src/pages/en/blog/[slug].astro
will return /en/blog/[slug]
for context.routePattern
. Every page on your site generated by that file (e.g. /en/blog/post-1/
, /en/blog/post-2/
, etc.) shares the same value for context.routePattern
. In the case of index.*
routes, the route pattern will not include the word “index.” For example, src/pages/index.astro
will return /
.
You can use this property to understand which route is rendering your component. This allows you to target or analyze similarly-generated page URLs together. For example, you can use it to conditionally render certain information, or collect metrics about which routes are slower.
See also: Astro.routePattern
context.isPrerendered
Section titled context.isPrerenderedType: boolean
astro@5.0.0
ベータ
A boolean representing whether or not the current page is prerendered.
You can use this property to run conditional logic in middleware, for example, to avoid accessing headers in prerendered pages.
See also: Astro.isPrerendered
getStaticPaths()
Section titled getStaticPaths()Type: (options: GetStaticPathsOptions) => Promise<GetStaticPathsResult> | GetStaticPathsResult
If a page uses dynamic params in the filename, that component will need to export a getStaticPaths()
function.
This function is required because Astro is a static site builder. That means that your entire site is built ahead of time. If Astro doesn’t know to generate a page at build time, your users won’t see it when they visit your site.
The getStaticPaths()
function should return an array of objects to determine which paths will be pre-rendered by Astro.
It can also be used in static file endpoints for dynamic routing.
When using TypeScript, use the GetStaticPaths
type utility to ensure type-safe access of your params
and props
.
The getStaticPaths()
function executes in its own isolated scope once, before any page loads. Therefore you can’t reference anything from its parent scope, other than file imports. The compiler will warn if you break this requirement.
params
Section titled paramsThe params
key of every returned object tells Astro what routes to build. The returned params must map back to the dynamic parameters and rest parameters defined in your component filepath.
params
are encoded into the URL, so only strings are supported as values. The value for each params
object must match the parameters used in the page name.
For example, suppose that you have a page at src/pages/posts/[id].astro
. If you export getStaticPaths
from this page and return the following for paths:
Then Astro will statically generate posts/1
, posts/2
, and posts/3
at build time.
Data Passing with props
Section titled Data Passing with propsTo pass additional data to each generated page, you can also set a props
value on every returned path object. Unlike params
, props
are not encoded into the URL and so aren’t limited to only strings.
For example, suppose that you generate pages based off of data fetched from a remote API. You can pass the full data object to the page component inside of getStaticPaths
:
You can also pass a regular array, which may be helpful when generating or stubbing a known list of routes.
Then Astro will statically generate posts/1
and posts/2
at build time using the page component in pages/posts/[id].astro
. The page can reference this data using Astro.props
:
paginate()
Section titled paginate()Pagination is a common use-case for websites that Astro natively supports via the paginate()
function. paginate()
will automatically generate the array to return from getStaticPaths()
that creates one URL for every page of the paginated collection. The page number will be passed as a param, and the page data will be passed as a page
prop.
paginate()
has the following arguments:
data
- array containing the page’s data passed to thepaginate()
functionoptions
- Optional object with the following properties:pageSize
- The number of items shown per page (10
by default)params
- Send additional parameters for creating dynamic routesprops
- Send additional props to be available on each page
paginate()
assumes a file name of [page].astro
or [...page].astro
. The page
param becomes the page number in your URL:
/posts/[page].astro
would generate the URLs/posts/1
,/posts/2
,/posts/3
, etc./posts/[...page].astro
would generate the URLs/posts
,/posts/2
,/posts/3
, etc.
The pagination page
prop
Section titled The pagination page propType: Page<TData>
Pagination will pass a page
prop to every rendered page that represents a single page of data in the paginated collection. This includes the data that you’ve paginated (page.data
) as well as metadata for the page (page.url
, page.start
, page.end
, page.total
, etc). This metadata is useful for things like a “Next Page” button or a “Showing 1-10 of 100” message.
page.data
Section titled page.dataType: Array<TData>
Array of data returned from the paginate()
function for the current page.
page.start
Section titled page.startType: number
Index of first item on current page, starting at 0
. (e.g. if pageSize: 25
, this would be 0
on page 1, 25
on page 2, etc.)
page.end
Section titled page.endType: number
Index of last item on current page.
page.size
Section titled page.sizeType: number
Default: 10
How many items per-page.
page.total
Section titled page.totalType: number
The total number of items across all pages.
page.currentPage
Section titled page.currentPageType: number
The current page number, starting with 1
.
page.lastPage
Section titled page.lastPageType: number
The total number of pages.
page.url.current
Section titled page.url.currentType: string
Get the URL of the current page (useful for canonical URLs). If a value is set for base
, the URL starts with that value.
page.url.prev
Section titled page.url.prevType: string | undefined
Get the URL of the previous page (will be undefined
if on the first page). If a value is set for base
, the URL starts with that value.
page.url.next
Section titled page.url.nextType: string | undefined
Get the URL of the next page (will be undefined
if on the last page). If a value is set for base
, the URL starts with that value.
page.url.first
Section titled page.url.firstType: string
Get the URL of the first page (will be undefined
if on the first page). If a value is set for base
, the URL starts with that value.
page.url.last
Section titled page.url.lastType: string
Get the URL of the last page (will be undefined
if on the last page). If a value is set for base
, the URL starts with that value.
page.url.first
Section titled page.url.firstType: string | undefined
astro@4.12.0
Get the URL of the first page (will be undefined
if on page 1). If a value is set for base
, prepend the base path to the URL.
page.url.last
Section titled page.url.lastType: string | undefined
astro@4.12.0
Get the URL of the last page (will be undefined
if no more pages). If a value is set for base
, prepend the base path to the URL.
import.meta
Section titled import.metaAll ESM modules include a import.meta
property. Astro adds import.meta.env
through Vite.
import.meta.env.SSR
can be used to know when rendering on the server. Sometimes you might want different logic, like a component that should only be rendered in the client: