Module dispatch_compiler

Description
Data Types
Function Index
Function Details

Compile dispatch rules to an Erlang module.

Authors: Marc Worrell (marc@worrell.nl).

Description

Compile dispatch rules to an Erlang module.

The dispatch compiler takes all the list of dispatch rules and creates an Erlang module that matches those rules.

The Erlang module exports a single function: match/2.

This function takes the binary request path, split on "/" and return the matched dispatch rule and list of bindings.

The dispatch function looks like:

  match([], Context) ->
       {ok, {{home, [], controller_page, [...]}, []}};
  match([<<"page">>, Id, Slug], Context) ->
       {ok, {{page, ["page", id, slug], controller_page, [...]}, [{id,Id}, {slug,Slug}]}};
  match([<<"lib">> | Star], Context) when Star =/= [] ->
       {ok, {{lib, ["lib", '*'], controller_file, [...]}, [{'*',Star}]}};
  match(_, _Context) ->
       fail.

Rules can also have conditions on their arguments. The condition are matched using the runtime dispatch_compiler:bind/3 function.

  match([<<"id">>, Foo] = Path, Context) ->
       case dispatch_compiler:runtime_bind(Path, ["id", id], Context) of
           {ok, Bindings} ->
               {ok, {{id, ["id", id], controller_id, [...]}, Bindings}};
           fail ->
               match1(Path, Context)
       end;
  match(Path, Context) ->
       match1(Path, Context).
 
  match1(..., Context) ->
       ...
  match1(_, _Context) ->
       fail.

Data Types

binding()

binding() = {atom(), binary() | [binary() | any()]}

dispatch_rule()

dispatch_rule() = {Name::atom(), dispatch_rule_path(), Handler::any(), HandlerArgs::list()}

dispatch_rule_path()

dispatch_rule_path() = [dispatch_rule_token()]

dispatch_rule_token() = binary() | '*' | atom() | {atom(), {atom(), atom()}} | {atom(), {atom(), atom(), list()}} | {atom(), match_function()} | {atom(), RegExp::iodata() | unicode:charlist()} | {atom(), RegExp::iodata() | unicode:charlist(), Options::list()}

match_function()

match_function() = fun((binary(), any()) -> boolean() | {ok, any()}) | fun((binary()) -> boolean() | {ok, any()})

Function Index

compile/2	Compile Erlang module.
compile_load/2	Compile and load Erlang module.
match/3	Launch `Module` `match` function.
runtime_bind/3	Runtime callback for argument binding with checks on the arguments.

ModuleName = atom()
DLs = [dispatch_rule()]
Result = ok

Compile and load Erlang module.

match/3

match(Module, Tokens, Context) -> Result

Module = atom()
Tokens = [binary()]
Context = any()
Result = {ok, {dispatch_rule(), [binding()]}} | fail

Equivalent to Module:match(Tokens, Context).

Launch Module match function.

runtime_bind/3

runtime_bind(Pattern, Path, Context) -> Result

Pattern = list()
Path = [binary()]
Context = any()
Result = {ok, [binding()]} | fail

Runtime callback for argument binding with checks on the arguments. The checks can be a function, module-function, or regexp.

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