diff options
Diffstat (limited to 'src/api/router_macros.rs')
| -rw-r--r-- | src/api/router_macros.rs | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/src/api/router_macros.rs b/src/api/router_macros.rs new file mode 100644 index 00000000..8471407c --- /dev/null +++ b/src/api/router_macros.rs @@ -0,0 +1,190 @@ +/// This macro is used to generate very repetitive match {} blocks in this module +/// It is _not_ made to be used anywhere else +macro_rules! router_match { + (@match $enum:expr , [ $($endpoint:ident,)* ]) => {{ + // usage: router_match {@match my_enum, [ VariantWithField1, VariantWithField2 ..] } + // returns true if the variant was one of the listed variants, false otherwise. + use Endpoint::*; + match $enum { + $( + $endpoint { .. } => true, + )* + _ => false + } + }}; + (@extract $enum:expr , $param:ident, [ $($endpoint:ident,)* ]) => {{ + // usage: router_match {@extract my_enum, field_name, [ VariantWithField1, VariantWithField2 ..] } + // returns Some(field_value), or None if the variant was not one of the listed variants. + use Endpoint::*; + match $enum { + $( + $endpoint {$param, ..} => Some($param), + )* + _ => None + } + }}; + (@gen_parser ($keyword:expr, $key:ident, $query:expr, $header:expr), + key: [$($kw_k:ident $(if $required_k:ident)? $(header $header_k:expr)? => $api_k:ident $(($($conv_k:ident :: $param_k:ident),*))?,)*], + no_key: [$($kw_nk:ident $(if $required_nk:ident)? $(if_header $header_nk:expr)? => $api_nk:ident $(($($conv_nk:ident :: $param_nk:ident),*))?,)*]) => {{ + // usage: router_match {@gen_parser (keyword, key, query, header), + // key: [ + // SOME_KEYWORD => VariantWithKey, + // ... + // ], + // no_key: [ + // SOME_KEYWORD => VariantWithoutKey, + // ... + // ] + // } + // See in from_{method} for more detailed usage. + use Endpoint::*; + use keywords::*; + match ($keyword, !$key.is_empty()){ + $( + ($kw_k, true) if true $(&& $query.$required_k.is_some())? $(&& $header.contains_key($header_k))? => Ok($api_k { + $key, + $($( + $param_k: router_match!(@@parse_param $query, $conv_k, $param_k), + )*)? + }), + )* + $( + ($kw_nk, false) $(if $query.$required_nk.is_some())? $(if $header.contains($header_nk))? => Ok($api_nk { + $($( + $param_nk: router_match!(@@parse_param $query, $conv_nk, $param_nk), + )*)? + }), + )* + (kw, _) => Err(Error::BadRequest(format!("Invalid endpoint: {}", kw))) + } + }}; + + (@@parse_param $query:expr, query_opt, $param:ident) => {{ + // extract optional query parameter + $query.$param.take().map(|param| param.into_owned()) + }}; + (@@parse_param $query:expr, query, $param:ident) => {{ + // extract mendatory query parameter + $query.$param.take().ok_or_bad_request("Missing argument for endpoint")?.into_owned() + }}; + (@@parse_param $query:expr, opt_parse, $param:ident) => {{ + // extract and parse optional query parameter + // missing parameter is file, however parse error is reported as an error + $query.$param + .take() + .map(|param| param.parse()) + .transpose() + .map_err(|_| Error::BadRequest("Failed to parse query parameter".to_owned()))? + }}; + (@@parse_param $query:expr, parse, $param:ident) => {{ + // extract and parse mandatory query parameter + // both missing and un-parseable parameters are reported as errors + $query.$param.take().ok_or_bad_request("Missing argument for endpoint")? + .parse() + .map_err(|_| Error::BadRequest("Failed to parse query parameter".to_owned()))? + }}; + (@func + $(#[$doc:meta])* + pub enum Endpoint { + $( + $(#[$outer:meta])* + $variant:ident $({ + $($name:ident: $ty:ty,)* + })?, + )* + }) => { + $(#[$doc])* + pub enum Endpoint { + $( + $(#[$outer])* + $variant $({ + $($name: $ty, )* + })?, + )* + } + impl Endpoint { + pub fn name(&self) -> &'static str { + match self { + $(Endpoint::$variant $({ $($name: _,)* .. })? => stringify!($variant),)* + } + } + } + }; + (@if ($($cond:tt)+) then ($($then:tt)*) else ($($else:tt)*)) => { + $($then)* + }; + (@if () then ($($then:tt)*) else ($($else:tt)*)) => { + $($else)* + }; +} + +/// This macro is used to generate part of the code in this module. It must be called only one, and +/// is useless outside of this module. +macro_rules! generateQueryParameters { + ( $($rest:expr => $name:ident),* ) => { + /// Struct containing all query parameters used in endpoints. Think of it as an HashMap, + /// but with keys statically known. + #[derive(Debug, Default)] + struct QueryParameters<'a> { + keyword: Option<Cow<'a, str>>, + $( + $name: Option<Cow<'a, str>>, + )* + } + + impl<'a> QueryParameters<'a> { + /// Build this struct from the query part of an URI. + fn from_query(query: &'a str) -> Result<Self, Error> { + let mut res: Self = Default::default(); + for (k, v) in url::form_urlencoded::parse(query.as_bytes()) { + let repeated = match k.as_ref() { + $( + $rest => if !v.is_empty() { + res.$name.replace(v).is_some() + } else { + false + }, + )* + _ => { + if k.starts_with("response-") || k.starts_with("X-Amz-") { + false + } else if v.as_ref().is_empty() { + if res.keyword.replace(k).is_some() { + return Err(Error::BadRequest("Multiple keywords".to_owned())); + } + continue; + } else { + debug!("Received an unknown query parameter: '{}'", k); + false + } + } + }; + if repeated { + return Err(Error::BadRequest(format!( + "Query parameter repeated: '{}'", + k + ))); + } + } + Ok(res) + } + + /// Get an error message in case not all parameters where used when extracting them to + /// build an Enpoint variant + fn nonempty_message(&self) -> Option<&str> { + if self.keyword.is_some() { + Some("Keyword not used") + } $( + else if self.$name.is_some() { + Some(concat!("'", $rest, "'")) + } + )* else { + None + } + } + } + } +} + +pub(crate) use generateQueryParameters; +pub(crate) use router_match; |