Variable number of parameters

Question

User-867254022 posted

Sorry if this is a dup, tried searching for an existing question but the site continually reported "Site is currently down for maintenance".

Anyway my question is how to specify a route may takes in variable number of parameters and use attribute routing for Web API 2.0?

Example, i have a hamburger shop which allows customers to place orders by submitting an order by hitting a URLs. The only requirement, at least 1 ingredient must be specified.  After that as many ingredients may be specified and in my real api the set of param values are from a set of 40000 or more  items.  So for these would be two valid orders requests:

http://www.food.com/api/Hamburger/cheese/pickles/onions/mustard/mayo/lettuce/ketchup/bacon
Or
http://www.food.com/api/Hamburger/mayo/lettuce/ketchup

The best i could find for some sample, but didn't work (assuming c#):

[HttpGet]                                             
[Route( "api/Hamburger/{*options}")]
public void OrderHamburger( ??? ) {...}

Not sure what to use for the method's arguments. At first it felt like i should use "params string[] options", this failed, searching more found RoutingCollection.  But stepping into with a debugger the value for options is null.  Later i thought how about regex like ".../{options:regex((\w)+)}" -- assuming "(\w)+"  is group of words that may occur 1 to 'x' times.  No matter what i've attempted debugging in the variable for "options" is always null .

Any suggestions how i can go about this?   Thanks in advance.

Answer 1

User-782957977 posted

As you have n number of options, I would suggest following solution. Please use [FromUri] option

[HttpGet]                                             
         [Route( "api/Hamburger")]
         public void OrderHamburger([FromUri]string[] options)
        { 
        }

http://www.food.com/api/Hamburger?options=cheese&options=pickles&options=onions&options=mustard

Or

Use comma separated options

http://www.food.com/api/Hamburger?options=cheese,pickles,onions,mustard

 [HttpGet]                                             
         [Route( "api/Hamburger")]
         public void OrderHamburger(string options)
        {
            string[] optionsArray = options.Split(',');
        }

Answer 2

User-867254022 posted

Thanks you got me exactly what i needed,  also for anyone else out there who might need this and build on it, i experimented a little to see if I really understood this.

Seems for me the comma separated values worked easier as any & will add the values into a separate argument while duplicate "&param" will add items into the respective array, . 

http://www.food.com/api/Hamburger?ingredients=cheese,pickles,onions,mustard?location=Hawaii,Australia,Japan

In code you want:
public OrderHamburger( [FromUri]string[] ingredients,[FromUri]string[] location)
{

     string[] toppings  = ingredients[0].split(...);
     string[] locations  = location[0].split(...);

And a request like:
http://www.food.com/api/Hamburger?ingredients=cheese,pickles,onions,mustard&location=Hawaii,Australia,Japan&ingredients=tofu

The same web methods appears to work just find but you'll notice ingredients will have 2 items in the array.
     string[] toppings    = ingredients[0].split(...);   // ["cheese","pickles","onions","mustard"];
     string[] toppings2  = ingredients[1].split(...);  // ["tofu"] 

Hope this helps anyone that might need this as well.