HTTP POST to Many to Many relation using ASP.NET Web API - asp.net

Question

I am new to ASP.net (and programming in general) and I'm having trouble building a Web API. More specifically I need help in these two areas:
How to configure my DOCcontroller to post a new document (DOC table).
How to make the actual ajax post -- I am having trouble passing the EXT_GUID parameter. As it stands I get an error when I try to post. "Can't bind multiple parameters (doc and parentOwner) to the request's content."
Essentially this is for a simple document management system. I want Get/Post documents (DOC) by having the user supply an GUID from an external database (the EXT_GUID field) as a filter/parameter. Each document can have multiple EXT_GUIDs and each EXT_GUID can have multiple Documents (DOC). You can assume that the EXT_GUID fields we be populated prior to the http post.
This is the DOCcontroller code
//POST api/DOC
public HttpResponseMessage PostDOC(DOC doc, List<string> parentOwners)
{
if (ModelState.IsValid)
{
var parents = db.BIMs.Where(bx => parentOwners.Contains(bx.EXT_GUID));
foreach (var p in parents)
doc.Owners.Add(p);
db.DOCs.Add(doc);
db.SaveChanges();
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, doc);
response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = doc.Id }));
return response;
}
else
{
return Request.CreateResponse(HttpStatusCode.BadRequest);
}
}
This is my model setup -- EntityFramework codefirst stuff
public class EXT
{
public int Id { get; set; }
public string EXT_GUID { get; set; }
public int ProjectID { get; set; }
public virtual ICollection<DOC> DOCs { get; set; }
}
public class DOC
{
public int Id { get; set; }
public int ProjectID { get; set; }
public string Subject { get; set; }
public string Link { get; set; }
public virtual ICollection<EXT> EXTs { get; set; }
}
This is more Storage Model...
public StoreDBContext() : base("name=StoreDBContext")
{
}
public DbSet<EXT> EXTs { get; set; }
public DbSet<DOC> DOCs { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Set FLUENT API config for many to many here
modelBuilder.Entity<EXT>()
.HasMany(a => a.DOCs)
.WithMany()
.Map(x =>
{
x.MapLeftKey("EXT_Id");
x.MapRightKey("DOC_Id");
x.ToTable("EXTsDOCs");
});
}
AJAX Code
function AddDOC() {
var parentOwner = "{\"" + $('#txtaddEXT').val() + "\"}";
jQuery.support.cors = true;
var DOC = {
ProjectId: ProjectID,
Subject: $('#txtaddDOCSubject').val(),
Link: $('#txtaddDOCLink').val(),
parentOwner: parentOwner
};
$.ajax({
url: "http://localhost:54171/api/DOC/",
type: 'POST',
data: JSON.stringify(DOC),
contentType: "application/json;charset=utf-8",
success: function (data) {
WriteResponse(data);
},
error: function (x, y, z) {
alert(x + '\n' + y + '\n' + z);
}
});
}

Answer 1

What you receive from the client and what you will save in the database is two different things.
Your doc object is ok:
var DOC = {
ProjectId: ProjectID,
Subject: $('#txtaddDOCSubject').val(),
Link: $('#txtaddDOCLink').val(),
parentOwner: parentOwner
};
Now you need to change the server logic. Make a model like this:
public class DocReceivedModel
{
public int ProjectID { get; set; }
public string Subject { get; set; }
public string Link { get; set; }
public List<string> parentOwner { get; set; }
}
Then your PostDOC method will be:
public HttpResponseMessage PostDOC(DocReceivedModel docReceived)
{
if (ModelState.IsValid)
{
Doc newDoc = new Doc();
newDoc.ProjectID = docReceived.ProjectID
newDoc.Subject = docReceived.Subject
newDoc.Link = docReceived.Link
var parents = db.BIMs.Where(bx => docReceived.parentOwners.Contains(bx.EXT_GUID));
foreach (var p in parents)
newDoc.Owners.Add(p);
// I not see in your model Owners, maybe this is EXTs but I suppose you catch the idea
db.DOCs.Add(newDoc);
db.SaveChanges();
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, newDoc);
response.Headers.Location = new Uri(Url.Link("DefaultApi", new {id = newDoc.Id}));
return response;
}
else
{
return Request.CreateResponse(HttpStatusCode.BadRequest);
}
}