In my first Phoenix app, I have an action which serves an XML phonebook to a certain SIP handset. The handset has two ways of calling this action:
/gigaset?reqsrc=user&ln=foo # Search for a contact with the name 'foo'
/gigaset?reqsrc=auto&hm=12345 # Search for a contact with caller ID 12345
Since both have different queries I decided to pattern match based on the reqsrc parameter. But both action have some shared logic as well, so I put that in a separate method with the same name but different arity to apply limit and offset and render the view/template. It works, but is this the right way of doing things?
# User quering phonebook from Gigaset base
def gigaset(conn, params = %{"reqsrc" => "user"}) do
name = String.replace(params["ln"], "*", "%")
query = from e in Entry, where: ilike(e.name, ^name)
gigaset conn, query, params
end
# Caller ID from Gigaset base
def gigaset(conn, params = %{"reqsrc" => "auto"}) do
number = params["hm"]
query = from e in Entry, where: e.work == ^number or e.home == ^number or e.mobile == ^number
gigaset conn, query
end
# Finish query, render output
def gigaset(conn, query, params) do
limit = String.to_integer(params["count"])
offset = String.to_integer(params["first"]) - 1
query = from e in query, limit: ^limit, offset: ^offset
entries = Repo.all(query)
render conn, entries: entries
end
I know the difference in the query is trivial, but imagine they would be vastly different. Does it make sense to do it like this?
Wait… after testing it again it seems to not work as expected
Requesting /gigaset?reqsrc=auto yields a ‘no matching action clause to process request’ error on the definition of the first method. Is there a way to do this, at all?
I ended up rewriting into this long method (with some more changes):
def gigaset(conn, params = %{ "reqsrc" => reqsrc, "count" => limit, "first" => offset }) do
query = case reqsrc do
# User quering phonebook from Gigaset base
"user" ->
name = String.replace(params["ln"], "*", "%")
from e in Entry, where: ilike(e.name, ^name)
# Caller ID from Gigaset base
"auto" ->
number = params["hm"]
from e in Entry, where: e.work == ^number or e.home == ^number or e.mobile == ^number
end
# Total before pagination
total = Repo.one(from e in query, select: count(e.id))
# Paginated entries
offset = String.to_integer(offset) - 1
query = from e in query, limit: ^limit, offset: ^offset
entries = Repo.all(query)
render conn, entries: entries, total: total, offset: offset
end
All feedback is welcome! I realise some of this belongs in the model probably.
Your match does only “fire” when you have all the parameters "reqsrc", "count", and "first" available. In the requested “path” /gigaset?reqsrc=auto" there is only "reqsrc" available, so you need to add another clause after your current one, which needs to be like this: