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authorElizabeth Hunt <me@liz.coffee>2025-07-27 17:03:10 -0700
committerElizabeth Hunt <me@liz.coffee>2025-07-27 18:30:30 -0700
commit9970036d203ba2d0a46b35ba6fad21d49441cdd4 (patch)
treea585d13933bf4149dcb07e28526063d071453105 /lib/server/filter
downloadpengueno-9970036d203ba2d0a46b35ba6fad21d49441cdd4.tar.gz
pengueno-9970036d203ba2d0a46b35ba6fad21d49441cdd4.zip
hai
Diffstat (limited to 'lib/server/filter')
-rw-r--r--lib/server/filter/index.ts34
-rw-r--r--lib/server/filter/json.ts42
-rw-r--r--lib/server/filter/method.ts30
3 files changed, 106 insertions, 0 deletions
diff --git a/lib/server/filter/index.ts b/lib/server/filter/index.ts
new file mode 100644
index 0000000..509deb3
--- /dev/null
+++ b/lib/server/filter/index.ts
@@ -0,0 +1,34 @@
+import {
+ type IEither,
+ type ITraceable,
+ LogLevel,
+ type PenguenoRequest,
+ type ServerTrace,
+} from '@emprespresso/pengueno';
+
+export enum ErrorSource {
+ USER = LogLevel.WARN,
+ SYSTEM = LogLevel.ERROR,
+}
+
+export class PenguenoError extends Error {
+ public readonly source: ErrorSource;
+ constructor(
+ override readonly message: string,
+ public readonly status: number,
+ ) {
+ super(message);
+ this.source = Math.floor(status / 100) === 4 ? ErrorSource.USER : ErrorSource.SYSTEM;
+ }
+}
+
+export interface RequestFilter<
+ T,
+ Err extends PenguenoError = PenguenoError,
+ RIn = ITraceable<PenguenoRequest, ServerTrace>,
+> {
+ (req: RIn): IEither<Err, T> | Promise<IEither<Err, T>>;
+}
+
+export * from './method';
+export * from './json';
diff --git a/lib/server/filter/json.ts b/lib/server/filter/json.ts
new file mode 100644
index 0000000..bc53d47
--- /dev/null
+++ b/lib/server/filter/json.ts
@@ -0,0 +1,42 @@
+import {
+ Either,
+ type IEither,
+ type ITraceable,
+ LogLevel,
+ Metric,
+ PenguenoError,
+ type PenguenoRequest,
+ type RequestFilter,
+ type ServerTrace,
+ TraceUtil,
+} from '@emprespresso/pengueno';
+
+export interface JsonTransformer<R, ParsedJson = unknown> {
+ (json: ITraceable<ParsedJson, ServerTrace>): IEither<PenguenoError, R>;
+}
+
+const ParseJsonMetric = Metric.fromName('JsonParse').asResult();
+export const jsonModel =
+ <MessageT>(jsonTransformer: JsonTransformer<MessageT>): RequestFilter<MessageT> =>
+ (r: ITraceable<PenguenoRequest, ServerTrace>) =>
+ r
+ .flatMap(TraceUtil.withFunctionTrace(jsonModel))
+ .flatMap(TraceUtil.withMetricTrace(ParseJsonMetric))
+ .map((j) =>
+ Either.fromFailableAsync<Error, MessageT>(<Promise<MessageT>>j.get().req.json()).then((either) =>
+ either.mapLeft((errReason) => {
+ j.trace.traceScope(LogLevel.WARN).trace(errReason);
+ return new PenguenoError('seems to be invalid JSON (>//<) can you fix?', 400);
+ }),
+ ),
+ )
+ .flatMapAsync(TraceUtil.promiseify(TraceUtil.traceResultingEither(ParseJsonMetric)))
+ .map(
+ TraceUtil.promiseify((traceableEitherJson) =>
+ traceableEitherJson
+ .get()
+ .mapRight((j) => traceableEitherJson.move(j))
+ .flatMap(jsonTransformer),
+ ),
+ )
+ .get();
diff --git a/lib/server/filter/method.ts b/lib/server/filter/method.ts
new file mode 100644
index 0000000..7d6aa76
--- /dev/null
+++ b/lib/server/filter/method.ts
@@ -0,0 +1,30 @@
+import {
+ Either,
+ HttpMethod,
+ IEither,
+ type ITraceable,
+ LogLevel,
+ PenguenoError,
+ type PenguenoRequest,
+ type RequestFilter,
+ type ServerTrace,
+ TraceUtil,
+} from '@emprespresso/pengueno';
+
+export const requireMethod =
+ (methods: Array<HttpMethod>): RequestFilter<HttpMethod> =>
+ (req: ITraceable<PenguenoRequest, ServerTrace>) =>
+ req
+ .flatMap(TraceUtil.withFunctionTrace(requireMethod))
+ .map((t): IEither<PenguenoError, HttpMethod> => {
+ const {
+ req: { method },
+ } = t.get();
+ if (!methods.includes(method)) {
+ const msg = "that's not how you pet me (â‹Ÿīšâ‹ž)~";
+ t.trace.traceScope(LogLevel.WARN).trace(msg);
+ return Either.left(new PenguenoError(msg, 405));
+ }
+ return Either.right(method);
+ })
+ .get();