Table of Contents

Team & user icons

The platform gives teams and users real icons/avatars beyond email-based Gravatar. It's built on two pluggable seams — storage (where bytes live) and sourcing (where a displayed image comes from) — each with a working built-in default, so it works out of the box and can be swapped per site.

The two seams

IIconStore — storage

Where icon bytes are saved: SaveAsync(kind, ownerKey, bytes, contentType) → reference, LoadAsync, DeleteAsync. The reference (an id/URL) is what's persisted on the team/user record.

  • Built-in default: MongoIconStore (in Tharga.Team.MongoDB) — registered automatically by AddThargaTeamRepository, no extra package. Bytes live in their own Icon collection (keyed by reference), never inlined into the hot Team/User documents.
  • Custom: o.AddIconStore<T>() for Azure Blob, S3, an existing DMS, etc. A custom store wins over the built-in one.

IIconSource — sourcing

Where a displayed image comes from. An IIconResolver runs the registered sources in order and returns the first non-null image; when none match, the avatar renders initials. Built-in sources, in order:

  1. StoredIconSource — an explicitly-set (uploaded) icon. Registered first, so a stored icon takes precedence.
  2. consumer sources — o.AddIconSource<T>(), so a host can supply images from its own system.
  3. GravatarIconSource — for users with an email (when enabled).
  4. DefaultIconSource — a configured generic default image, if any.

Resolution: stored icon → custom sources → Gravatar → default image → initials.

Options

IconOptions (upload limits — startup)

Property Default Meaning
MaxBytes 256 KB Max stored size, validated after processing.
MaxUploadBytes 10 MB Max original upload accepted for reading, before downscaling.
MaxDimension 256 Max width/height (px) an image processor downscales to. 0 disables.
AllowedContentTypes png, jpeg, gif, webp, svg Accepted image types.

Configure via o.Icon on AddThargaTeam.

IconSettings (display/behavior — runtime-adjustable)

Registered as a singleton, so a host can change these at runtime (the sample has a page that does):

Property Default Meaning
GravatarEnabled true Use Gravatar as a fallback for users without an uploaded icon.
GravatarStyle identicon Gravatar default-image style (identicon, monsterid, retro, robohash, mp, …).
DefaultUserIconUrl null A generic default image for users (after/instead of Gravatar).
AllowUserUpload true Whether users can upload their own icon.
AllowAdminUpload true Whether admins (users:manage) can upload an icon for a user.

Configure initial values via o.IconSettings.

Team icons

ITeam.Icon already exists on TeamEntityBase, so team icons need no entity change. A team:manage holder sets a team icon from the team-management component (TeamComponent → the Actions button): upload a file or point at an image URL (downloaded server-side). The operations — ITeamService.SetTeamIconAsync / ClearTeamIconAsync — are gated by team:manage and audited (icon-set / icon-clear); replacing or clearing deletes the previous blob. Rendered by <TeamAvatar> (teams list, card title, team selector) with an initials fallback.

User icons

Opt in by declaring Icon on your user entity (the same shape-based opt-in as DirectoryId/LastSeen):

public record UserEntity : EntityBase, IUser
{
    public required string Key { get; init; }
    public required string Identity { get; init; }
    public required string EMail { get; init; }
    public string Name { get; init; }
    public string Icon { get; init; }   // opt in to user icons
}

Without that property, uploads are refused. The reference write is a no-op on an entity that does not declare Icon, so an upload used to store the image bytes, silently discard the reference, and report success — an unchanged avatar, an orphan in the icon store, and nothing logged. Both SetOwnIconAsync and SetUserIconAsync now throw NotSupportedException naming the entity type, before any bytes are written. If you see it, declare the property.

Forwarding IIconStore in a service subclass

MongoIconStore being registered by AddThargaTeamRepository is necessary but not sufficient. TeamServiceRepositoryBase and UserServiceRepositoryBase take the store as an optional constructor parameter, so a subclass that does not forward it receives null and every icon operation throws — even though the store is correctly registered:

public class UserService(
    IUserRepository<UserEntity> repository,
    IHttpContextAccessor httpContextAccessor,
    IIconStore iconStore = null)                       // accept it...
    : UserServiceRepositoryBase<UserEntity>(repository, httpContextAccessor, iconStore)   // ...and forward it
{
}

Omit the parameter and the failure reads as a registration problem, which sends you to look in the wrong place. The exception text names both causes for that reason.

  • Self-service: the profile page's Change picture action (IUserService.SetOwnIconAsync / ClearOwnIconAsync) lets a user upload their own icon as an alternative to Gravatar (gated by IconSettings.AllowUserUpload). The top-right profile avatar refreshes live.
  • Administrative: on the users admin list, Set icon (IUserService.SetUserIconAsync, gated by users:manage + IconSettings.AllowAdminUpload) lets an admin set a user's icon.

Rendered by <UserAvatar> everywhere a user is shown (top-right menu, users list, member grids), which resolves stored → Gravatar → initials.

Serving endpoint

Stored icons are served at GET /_tharga/icon/{reference} to authenticated callers, with an immutable cache header (the reference changes when the icon changes).

UseThargaTeam maps it for you. On the granular setup path, map it yourself — see below.

The granular setup path

Hosts using AddThargaAuth + AddThargaTeamBlazor rather than the AddThargaTeam facade need no extra icon registration: AddThargaTeamBlazor registers the whole chain (IconSettings, the icon sources, IIconResolver, AvatarChangeNotifier). Configure it on the same options object the facade uses:

builder.AddThargaTeamBlazor(o =>
{
    o.IconSettings.AllowUserUpload = false;
    o.Icon.MaxBytes = 512 * 1024;
    // o.AddIconStore<MyStore>();  o.AddIconSource<MySource>();
});

var app = builder.Build();
app.UseThargaAuth();
app.UseThargaTeamBlazor();   // maps GET /_tharga/icon/{reference}

UseThargaTeamBlazor is the counterpart to AddThargaTeamBlazor, mirroring AddThargaAuth/UseThargaAuth. Skip it and avatars still render — stored icons simply 404, falling back to Gravatar or initials.

Upgrading from an earlier version? The icon chain used to be registered only inside the facade, so LoginDisplay — which is in the layout and therefore renders on every page — threw on the granular path and took the Blazor circuit with it. ValidateOnBuild could not warn you, because Blazor resolves @inject properties at render time rather than through the constructor graph it walks. If you added a hand-rolled registration block to work around that, delete it now that the library registers the chain itself.

Automatic squaring and downscaling — Tharga.Team.Images

Uploads larger than IconOptions.MaxBytes would be rejected. Add the optional Tharga.Team.Images package to instead fit images within MaxDimension (256 px), square them by padding the short side with transparency, and re-encode as PNG:

builder.Services.AddThargaImageProcessing();

It registers an IIconProcessor (SkiaSharp) that the built-in store runs before validating/storing. Formats it can't decode (e.g. SVG) pass through unchanged, as do images already square and within bounds. Bring your own by registering a custom IIconProcessor.

The package carries its own Linux native assets, so there is nothing to install on the host and slim or Alpine containers work as-is. From 3.11 it uses SkiaSharp (MIT); 3.10 and earlier used ImageSharp, whose Six Labors Split Licence requires a paid licence for closed-source for-profit use above $1M annual gross revenue — so if you held one on this package's account, you no longer need it. The processor type was renamed ImageSharpIconProcessor → SkiaIconProcessor in the same release, which only affects code that registered it by hand rather than calling AddThargaImageProcessing(). Output is unchanged.

What squaring produces

Content is never cropped and never upscaled. The output side is min(max(width, height), MaxDimension) — so an image that already fits is padded at its own size rather than blown up to the box:

Source Output Why
1000×500 256×256 scaled to 256×128, then padded
100×50 100×100 already fits, so padded only
50×100 100×100 tall sources take the same path
300×300 256×256 square, but larger than the box
100×100 unchanged square and within bounds — the only pass-through case

The point is avatar surfaces that reserve a square box: before squaring, each letterboxed a wide or tall source in its own way. Cropping would square them too, and is precisely the failure to avoid — it takes a face out of a portrait photo.

Important

Behaviour change. Output previously preserved the source aspect ratio, so a 1000×500 upload was stored as 256×128. New uploads are now squared. Already-stored icons are not reprocessed — there is no migration, and existing avatars keep their current shape until someone re-uploads.

The upload dialogs say which behaviour is in effect. Without a real processor the default is NoOpIconProcessor, which does not resize, so the dialog reads "Images larger than N MB are rejected" rather than promising processing that will not happen. Add the package and it switches to "Images are squared and downscaled automatically — the short side is padded, never cropped." IconCapability.CanProcessImages(processor) is the same check if you need it in your own UI.

Quick start

// Built-in Mongo store + Gravatar are automatic. Add downscaling and map admin/user upload to a role:
builder.Services.AddThargaImageProcessing();                 // optional: auto-downscale

builder.AddThargaTeam(o =>
{
    o.Icon.MaxDimension = 256;                               // resize target
    o.IconSettings.GravatarStyle = "identicon";              // or disable: o.IconSettings.GravatarEnabled = false
    o.ConfigureSystemRoles = roles => roles.Map("Developer", SystemUserScopes.Manage); // admin upload
});

Team icons work with no entity change; add Icon to your user entity for user icons.

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