TypeScript client transport

Client transport implementation

Every project has it's custom transport implementation. It typically is a good place for:

• http header handling for requests and responses eg adding trace ids
• custom handling of client vs server side transports (browser vs Node.js)
• central error handling
• client activity tracking

example transport

// every project has special needs for their flavour of transport this is a
// naive vanilla implementation
const transport =
  (endpoint: string) =>
  async <T>(method: string, args: any = []) => {
    return new Promise<T>(async (resolve, reject) => {
      fetch(`${endpoint}/${encodeURIComponent(method)}`, {
        method: "POST",
        body: JSON.stringify(args),
      })
        .then((response) => {
          return response.json() as Promise<T>;
        })
        .then((val) => resolve(val))
        .catch((err) => reject(err));
    });
  };

Client client construction

Client construction is also project specific.

• special handling of server side endpoints
• adding transport middlewares
• passing through client request headers and cookies on the server side

This is a minimal client side client constructor:

example client construction

// every generated gotsrpc client implements this interface
export interface ServiceConstructor<ST> extends Function {
  defaultEndpoint: string;
  prototype: ST;
  new (transport: <T>(method: string, data?: any[]) => Promise<T>): ST;
}

// this client for client construction
export const getClient = <T>(clientClass: ServiceConstructor<T>) => {
  return new clientClass(transport('http://localhost:8080'+clientClass.defaultEndpoint));
};