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/// 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;
|
