Breeze failing silently while parsing metadata - metadata

Question

Trying to get going on breeze but encountering the worst kind of error, which is none at all. It appears the metadata that I am producing is not being accepted by breeze. I know currently there are some issues with the metadata, such as 'foreignKeyNamesOnServer' has incorrect values in it and a bunch of others. The metadata I am producing can be viewed here (too large):
http://pastebin.com/ycP4jXxn
var serviceName = 'http://www.dockyard.com:8080/rest';
var entityManager = new breeze.EntityManager({serviceName: serviceName});
var entityQuery = new breeze.EntityQuery();
var query = breeze.EntityQuery.from("application")
entityManager.executeQuery(query)
.then(function (data) {
console.log(data);
}, function (error) {
console.log(error);
});
So the behaviour I am seeing is no javascript errors related to metadata parsing, the metadata is returning ok with 200 OK. The hit to /rest/application is returning 200 OK with the following data.
[{"#id":1,"id":1,"name":"dsad","deploymentStrategies":null,"versions":null,"groups":null},{"#id":2,"id":2,"name":"sss","deploymentStrategies":null,"versions":null,"groups":null},{"#id":3,"id":3,"name":"fdsfs","deploymentStrategies":null,"versions":null,"groups":null},{"#id":4,"id":4,"name":"fdsa","deploymentStrategies":null,"versions":null,"groups":null},{"#id":5,"id":5,"name":"dasda","deploymentStrategies":null,"versions":null,"groups":null}]
Promise is calling the error callback with: cannot execute _executeQueryCore until metadataStore is populated
The contents of the metadata store:
{"namingConvention":{"name":"camelCase"},"localQueryComparisonOptions":{"name":"caseInsensitiveSQL","isCaseSensitive":false,"usesSql92CompliantStringComparison":true},"dataServices":[{"serviceName":"http://www.dockyard.com:8080/rest/","hasServerMetadata":true,"jsonResultsAdapter":"webApi_default","useJsonp":false}],"_resourceEntityTypeMap":{"platform":"Platform:#com.psidox.dockyard.controller.model.dockyard","application":"Application:#com.psidox.dockyard.controller.model.application","host":"Host:#com.psidox.dockyard.controller.model.host","groupdeploymentstrategy":"GroupDeploymentStrategy:#com.psidox.dockyard.controller.model.application","dockyard":"Dockyard:#com.psidox.dockyard.controller.model.dockyard","configurationentry":"ConfigurationEntry:#com.psidox.dockyard.controller.model","hoststrategy":"HostStrategy:#com.psidox.dockyard.controller.model.application","dockerimage":"DockerImage:#com.psidox.dockyard.controller.model.docker","version":"Version:#com.psidox.dockyard.controller.model.application","docker":"Docker:#com.psidox.dockyard.controller.model.docker","hostproviderconfig":"HostProviderConfig:#com.psidox.dockyard.controller.model.host","hostprovider":"HostProvider:#com.psidox.dockyard.controller.model.host","metadataimpl":"MetadataImpl:#com.psidox.dockyard.controller.model","deployment":"Deployment:#com.psidox.dockyard.controller.model.dockyard","hosttype":"HostType:#com.psidox.dockyard.controller.model.host","group":"Group:#com.psidox.dockyard.controller.model.application","groupimplementation":"GroupImplementation:#com.psidox.dockyard.controller.model.application","deploymentstrategy":"DeploymentStrategy:#com.psidox.dockyard.controller.model.dockyard","groupdeployment":"GroupDeployment:#com.psidox.dockyard.controller.model.application","metadata":"Metadata:#com.psidox.dockyard.controller.model"},"_structuralTypeMap":{},"_shortNameMap":{},"_ctorRegistry":{},"_incompleteTypeMap":{},"_incompleteComplexTypeMap":{},"_id":0,"_deferredTypes":{}}"
I am pretty sure this error is related to Metadata store not being populated correctly from my metadata. Just wondering why Breeze is not throwing any type of error when it is encountering invalid metadata?
Edit:
After debugging the parse metadata call it appears that Breeze Metadata Schema Documentation is out of date. At a quick glance this is what it looks like has changed:
Key name "structuralTypeMap" has changed to "structuralTypes".
"structuralTypeMap" use to be a object with the key as the EntityTypeName and value was the Entity definition. Now it appears that "structuralTypes" is an array with the Entity definitions.
Suggestions also there should possibly be an exception thrown if the metadata doesn't contain any structuralTypes? Currently it is failing silently which isn't very helpful for debugging.

Answer 1

I fear they you've jumped into the deep end of the pool before learning to swim. I admire your bravery but I'm not surprised that you're struggling to stay afloat. You're not following any of the easy paths we've set out for you. I assume that is because none of these paths are suitable to your situation.
On the bright side, you've reinforced by sense that we soon must make it easier for developers who get their data from a custom REST service.
Problem #1
The Query results do not identify the EntityType and you didn't mention that you wrote a custom JsonResultsAdapter to cope with that. Your question and your MetadataStore contents below suggest that you are using the out-of-the-box Web API adapter which wouldn't know what to do with the JSON query results.
Here is one item in the JSON payload from your query, reformatted for readability
{
"#id": 1,
"id": 1,
"name": "dsad",
"deploymentStrategies": null,
"versions": null,
"groups": null
}
There's nothing in there to indicate to which EntityType this data belongs. Just looking I have no idea what type this is. Breeze won't know either.
You'll need to learn about the "JsonResultsAdapter" which is how Breeze interprets JSON data arriving from the server and maps it into instances of EntityTypes.
The Ruby Sample has a custom JsonResultsAdapter. It depends upon the fact that the server is explicit about the type of each object it returns; see how every Rails view adds a $type node (for example, the sessions:index view). This is the approach to take if you can control what the server sends the client.
The Edmunds Sample has a custom JsonResultsAdapter that has to infer the type by examining the characteristics of the JSON data. It's kind of a forensic exercise that you only want to indulge if you have to do so.
Problem #2
The MetadataStore you serialized is empty of all type information. Here it is reformatted for legibility
{
"namingConvention": {
"name": "camelCase"
},
"localQueryComparisonOptions": {
"name": "caseInsensitiveSQL",
"isCaseSensitive": false,
"usesSql92CompliantStringComparison": true
},
"dataServices": [
{
"serviceName": "http:\/\/www.dockyard.com:8080\/rest\/",
"hasServerMetadata": true,
"jsonResultsAdapter": "webApi_default",
"useJsonp": false
}
],
"_resourceEntityTypeMap": {
"platform": "Platform:#com.psidox.dockyard.controller.model.dockyard",
"application": "Application:#com.psidox.dockyard.controller.model.application",
... a bunch more ...
},
"_structuralTypeMap": {
},
"_shortNameMap": {
},
... more emptiness ...
}
}
I'm not really surprised, having discovered problem #3.
Problem #3
Your raw metadata doesn't match a format that Breeze understands. It looks like you cobbled it together by hand. It sure doesn't look like anything I recognize. It doesn't match the CSDL format from Entity Framework. It doesn't match the "Breeze Metadata Format" that you'd see when you exported a MetadataStore.
It's in trouble almost immediately. Here is how you start the definition of your first type:
"structuralTypeMap": {
"Group:#com.psidox.dockyard.controller.model.application": {
"shortName": "Group",
"namespace": "com.psidox.dockyard.controller.model.application",
Here is how it should begin:
"structuralTypes": [
{
"shortName": "Group",
"namespace": "com.psidox.dockyard.controller.model.application",
I accept your point that the Breeze Metadata Schema Documentation is incorrect. We should fix that.
I'm sympathetic with your argument that Breeze should have thrown an exception. I can see why it didn't throw. It simply ignored all the nodes that it didn't understand. A lot of parsers do that, not that that is a sufficient excuse.
In this case, it ignored the "structuralTypeMap" node and everything it had to say about types. When the parser was done, it had learned nothing at all about the types. Breeze can't know how many types you'll specify but it could act suspicious if there are none.
I confess I personally never thought to use this metadata schema description as my guide. That would be just about the hardest possible way to write metadata.
I suggest that you look at the documentation topic "Metadata by hand".
In sum
Please examine a simple example first. Maybe Edmunds. Maybe Ruby.
Learn to write metadata by hand; it's not hard.
Learn about the JsonResultsAdapter
We do hope soon to offer specific guidance for the developer who has a "vanilla" REST data service.