Hands-On Microservices with Rust

Publish channel

We will add a method that sets the is_public flag of a channel record to true. Look at the following implementation:

pub fn publish_channel(&self, channel_id: Id) -> Result<(), Error> {    let channel = channels::table        .filter(channels::id.eq(channel_id))        .select((                channels::id,                channels::user_id,                channels::title,                channels::is_public,                channels::created_at,                channels::updated_at,                ))        .first::<Channel>(&self.conn)        .optional()        .map_err(Error::from)?;    if let Some(channel) = channel {        diesel::update(&channel)            .set(channels::is_public.eq(true))            .execute(&self.conn)?;        Ok(())    } else {        Err(format_err!("channel not found"))    }}

The function expects channel_id, and we use the table value to create a statement. We use the filter method of ...