[Bug] AvatarView does not load Initials on UriImageSource with HTTP 204 (no content)

[jslachta]

Description

I am not sure whether this should go for Xamarin.Forms or XCT.

Let's say we have a list of persons. Some of them have a picture, and some of them do not have a picture.

In the case of HTTP status code 204 (HTTP status code for no content), the AvatarView shows empty AvatarView instead of showing Initials. In the case of HTTP status codes higher than 400, the AvatarView loads initials correctly.

I consider it as a bug because:

• an entity not having a picture is an expected state. It is not an error (404). It is no-content (204).
• the UriImageSource will return null stream on exception (HTTP status code >= 400)
• exceptions should be exceptional, and exception handling is performance-hungry

Steps to Reproduce

<xct:AvatarView 
                    Grid.Row="0"
                    Grid.RowSpan="3"
                    Grid.Column="0"
                    FontSize="Medium"
                    Size="40"
                    Text="{Binding Initials}">
                    <xct:AvatarView.Source>
                        <UriImageSource 
                            CacheValidity="00:30:00"
                            CachingEnabled="True" 
                            Uri="{Binding ImageUrl}" />
                    </xct:AvatarView.Source>
</xct:AvatarView>

1. For an AvatarView defined above provide in ImageUrl an Uri returning HTTP 204.

Expected Behavior

Providing an empty picture:

• HTTP 200: empty AvatarView shown, no Initials
• HTTP 204 - for no content I cannot provide a picture in response body: Initials shown
• HTTP >=400: Initials shown

Actual Behavior

Providing an empty picture:

• HTTP 200: empty AvatarView shown, no Initials (OK)
• HTTP 204: empty AvatarView shown, no Initials (NOK)
• HTTP >=400: Initials shown (OK)

Basic Information

• Version with issue: 1.1.0
• Last known good version: none
• IDE: 16.9.2
• Platform Target Frameworks:
  • iOS: not tested
  • Android: 11.0
  • UWP: not tested
• Android Support Library Version: none
• Nuget Packages:
• Affected Devices: all

Workaround

Return HTTP status code >= 400.

Reproduction imagery

None.

Reproduction Link

None.

[AndreiMisiukevich]

@jslachta hm, we definitely need a sample of such image.

[jslachta]

@AndreiMisiukevich, I have some troubles with providing a repro. I have currently so little time to debug it.

• I have created sample WebApi project with ASP.NET Core. This provides 2 methods, one returns Xamarin logo, and the second one returns No content.
• There is also a Xamarin Forms project with two avatarviews, one pointing to the method providing an image, and the second one to no-content method.

I might have overlooked something, in my private Xamarin Forms application the AvatarView works as in the description, in the demo it does not load anything and shows initials for both avatarviews.

The first repro attempt is here. There is a short readme for the reproduction.

I have tried the changes from pull request in my closed source project and the proposed changes makes it working. The initials were shown correctly.