Path parameters in Angular2

问题:

How are we meant to handle path parameters in Angular 2 when doing RESTful calls to a Web Service?

I've found the URLSearchParams object for query parameters but from what I have found it seems we'll have to make do with string-concatenation for the path itself. Like

let url = 'api/v1/something/' + encodeURIComponent(someParameter) + 
          '/etc/' + encodeURIComponent(anotherParam) + '/and/so/on';

Is there, included in angular2, something that does similar to:

let url = new URL('api/v1/something/{id}/etc/{name}/and/so/on', param1, param2);

I can of course create something similar myself but prefer if there is something included in angular2.

回答1:

Indeed, you can use string interpolation and nearly exactly the same thing you suggest, assuming id and name are already set and encoded.

let url = new URL(`api/v1/something/${id}/etc/${name}/and/so/on`);

I'll note that currently the ES6 URL class only supports searchParams, but has no notion of path parameters.

Also, I know of no method that will automatically encode your parameters without implementing your own QueryEncoder with URLSearchParams

回答2:

If anybody is interested, this is what I ended up doing:

export interface PathParameters {
  [parameterName: string]: string;
}

export class Url {

  public static create(url: string, parameters: PathParameters) {
    const placeholders = url.match(/({[a-zA-Z]*})/g);
    placeholders.forEach((placeholder: string) => {
      const key = placeholder.substr(1, placeholder.length - 2);
      const value = parameters[key];
      if (!value) {
        throw new Error(`parameter ${key} was not provided`);
      }
      url = url.replace(placeholder, encodeURIComponent(value));
    });
    return url;
  }

}

How to use:

const url = Url.create('/api/cars/{carId}/parts/{partId}', {
    carId: carId,
    partId: partId
  });