In image block, unfetchable image_url leads to message never posted instead of falling back to alt_text or fallback #1396
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adrian-heouairi
changed the title
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Hi there, It's the expected behaviour that the You could try using a section block with an image element, which would still send the message if the image URL is broken. (The client will show a placeholder if the image cannot be fetched) |
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Hello, I tried (or so I think) what you suggested: section block with an image element. Here is the Kotlin code: withBlocks {
section {
markdownText(text)
}
section {
this@withBlocks.image {
val title = imageTitle ?: "Attached image"
title(title)
fallback(title)
altText(title)
imageUrl("http://localhost:8091/timeout.jpg")
}
}
}The message is never posted for any URL, valid, 404 or timeout. I even tried to trigger a SocketTimeoutException by using a local server that just sleeps on any GET, no exception is there, nothing in our logs. We also tried another solution that works: using an accessory image: withBlocks {
section {
markdownText(text)
accessory {
image(
//imageUrl = "https://www.google.com/images/branding/googlelogo/1x/googlelogo_color_272x92dp.png",
imageUrl = "http://localhost:8091/timeout.jpg",
altText = "alt text",
)
}
}
}With the accessory any URL works (valid, 404, timeout) (in case of invalid URL the message is posted with a broken icon). Unfortunately it doesn't fit all use cases as the thumbnail is small. |
It seems that on chatPostMessage of a message containing an image block, the SDK tries to fetch the image located at image_url with OkHttp 4.11.0 and any other result than a successful image fetch leads to chatPostMessage failing silently and never posting the message, e.g. any response code other than HTTP 200 fails silently and the special case of an HTTP timeout leads to a SocketTimeoutException.
The Slack SDK version
Gradle
versions.properties:Java Runtime version
OS info
Reproduced in local:
Note that this is also reproduced when deployed on our AWS (I don't know the architecture details).
Steps to reproduce:
build.gradle.ktsbits that may be relevant:asyncMethodsClient.chatPostMessage { it.text("Something") .blocks(withBlocks { section { markdownText("Something") } image { title("Attached image") fallback("Attached image") altText("Attached image") imageUrl("https://www.google.com/gives_a_404.jpg") } }) .channel(originalMessage.channelId) .threadTs(originalMessage.id) }Expected result:
Message should be posted without image and with the alt_text or fallback.
Actual result:
Message is never posted, nothing in logs for example with a 404 image URL. With a URL that times out, we get the following logs:
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