Allows CAS SSO flow to provide user IDs composed of numbers only

[agrimpard]

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Signed-off-by: Aurélien Grimpard aurelien@grimpard.net

Why : We use CAS and we have user IDs with only numbers so we need a way to let them connect to Synapse with CAS

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[reivilibre]

wasn't entirely meaning to review right now, but just an early look with a few comments, seems fine overall but I should look a bit more closely

[clokep]

I think for the other SSO providers we suggest using templates for this!

[agrimpard]

I think for the other SSO providers we suggest using templates for this!

Are you thinking about user_mapping_provider ?
It is documented for OIDC but CAS is not inside OIDC and the parameter user_mapping_provider doesn't seems to be related to CAS.
https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#oidc_providers
https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#cas_config

[clokep]

I think for the other SSO providers we suggest using templates for this!

Are you thinking about user_mapping_provider ? It is documented for OIDC but CAS is not inside OIDC and the parameter user_mapping_provider doesn't seems to be related to CAS. matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#oidc_providers matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#cas_config

Yes -- I wasn't suggesting it exists, but that there's benefit in doing things the same across the providers. You'll need to ask @reivilibre which way he prefers though!

[erikjohnston]

I think we're happy to land this as is