Class UrlPreviewService

URL previews: fetch a page, read its OpenGraph title, description and image, and store the image in the media repository.

Inheritance

object

UrlPreviewService

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Uniform.Matrix.Server.Media

Assembly: Uniform.Matrix.Server.dll

Syntax

public sealed class UrlPreviewService

Remarks

Pages and images are fetched through PublicAddresses, so previews cannot reach machines inside the server's network unless AllowPrivateAddresses is on; size and time are limited. Results are kept for CacheDuration per address.

Constructors

UrlPreviewService(IHttpClientFactory, MediaService, IOptionsMonitor<UrlPreviewOptions>, TimeProvider, ILogger<UrlPreviewService>)

Create the service.

Declaration

public UrlPreviewService(IHttpClientFactory httpClients, MediaService media, IOptionsMonitor<UrlPreviewOptions> options, TimeProvider time, ILogger<UrlPreviewService> logger)

Parameters

Type	Name	Description
IHttpClientFactory	httpClients
MediaService	media
IOptionsMonitor<UrlPreviewOptions>	options
TimeProvider	time
ILogger<UrlPreviewService>	logger

Fields

HttpClientName

Name of the HTTP client that fetches pages.

Declaration

public const string HttpClientName = "Uniform.Matrix.Server.UrlPreviews"

Field Value

Type	Description
string

Properties

Enabled

Get whether previews are on, see Enabled.

Declaration

public bool Enabled { get; }

Property Value

Type	Description
bool

Methods

GetPreviewAsync(string, string, CancellationToken)

Return the preview of url: og: keys of the page, and the image as an mxc:// URI with matrix:image:size; an image link previews as itself.

Declaration

public Task<JsonObject> GetPreviewAsync(string userId, string url, CancellationToken cancellationToken)

Parameters

Type	Name	Description
string	userId	Who asks; owns the stored image.
string	url	Absolute http or https address.
CancellationToken	cancellationToken	Cancellation token.

Returns

Type	Description
Task<JsonObject>