Add Optional Metadata Parameter to Service Interface

Currently, the generated service interface methods accept a single parameter as an argument. Example: getPage(request: logbook.getPageRequest): Observable<logbook.Page>;

gRPC allows you to pass optional parameters to service calls in the form of metadata. This information is passed through correctly at the moment due to ...args spread, however the type signature causes the compiler to complain. I could just add things such as the JWT token to the request proto definition itself, but metadata feels like the appropriate use case.

Do you think it would be appropriate for the interface service definitions to include metadata as an optional parameter? getPage(request: logbook.getPageRequest, metadata?: any): Observable<logbook.Page>;

I can try to get a PR together if you’d like.

[MaikelH]

There is some work being done on getting an a typescript definition file for gRPC, see #11020. Luckily for us that contains a definition file, I copied the metadata part below.

With that definition we can type the metadata parameter:

getPage( request: logbook.getPageRequest, metadata ?: Metadata ): Observable<logbook.Page>;

Definition copied from index.d.ts

  export class Metadata {
    /**
     * Class for storing metadata. Keys are normalized to lowercase ASCII.
     */
    constructor();

    /**
     * Sets the given value for the given key, replacing any other values associated
     * with that key. Normalizes the key.
     * @param key The key to set
     * @param value The value to set. Must be a buffer if and only if the normalized key ends with '-bin'
     */
    set(key: string, value: string | Buffer): void;

    /**
     * Adds the given value for the given key. Normalizes the key.
     * @param key The key to add to.
     * @param value The value to add. Must be a buffer if and only if the normalized key ends with '-bin'
     */
    add(key: string, value: string | Buffer): void;

    /**
     * Remove the given key and any associated values. Normalizes the key.
     * @param key The key to remove
     */
    remove(key: string): void;

    /**
     * Gets a list of all values associated with the key. Normalizes the key.
     * @param key The key to get
     * @return The values associated with that key
     */
    get(key: string): (string | Buffer)[];

    /**
     * Get a map of each key to a single associated value. This reflects the most
     * common way that people will want to see metadata.
     * @return A key/value mapping of the metadata
     */
    getMap(): { [index: string]: string | Buffer };

    /**
     * Clone the metadata object.
     * @return The new cloned object
     */
    clone(): Metadata;
  }

[kondi]

Released in v0.2.0.