private async Task AlterAPerson(IDgraphClient client)
{
using (var transaction = client.NewTransaction()) {
Person3.Friends.Add(Person2);
// This will serialize the whole object. You might not want to
// do that, and maybe only add in the bits that have changed
// instead.
var json = JsonConvert.SerializeObject(Person3);
var result = await transaction.Mutate(json);
AssertResultIsSuccess(result, "Mutation failed");
// no nodes were allocated
result.Value.Count.Should().Be(0);
await transaction.Commit();
}
var queryPerson = await client.Query(FriendQueries.QueryByUid(Person3.Uid));
AssertResultIsSuccess(queryPerson, "Query failed");
FriendQueries.AssertStringIsPerson(queryPerson.Value, Person3);
}
private async Task DiscardedTransactionsHaveNoEffect(IDgraphClient client)
{
var txn1 = client.NewTransaction();
var person = MintAPerson(nameof(DiscardedTransactionsHaveNoEffect));
var json = JsonConvert.SerializeObject(person);
var transactionResult = await txn1.Mutate(json);
AssertResultIsSuccess(transactionResult);
person.Uid = transactionResult.Value[person.Uid.Substring(2)];
await txn1.Discard();
// Can we see it
var queryByName = await client.QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", person.Name }
});
AssertResultIsSuccess(queryByName);
queryByName.Value.Should().Be("{\"q\":[]}");
// Can we see it in the uid (note that uid queries always return the
// uid ... we are interested if returns the actual person or not)
var queryByUid = await client.Query(FriendQueries.QueryByUid(person.Uid));
AssertResultIsSuccess(queryByUid);
queryByUid.Value.Should().Be($"{{\"q\":[{{\"uid\":\"{person.Uid}\"}}]}}");
}
private async Task UnrelatedTransactionsDoNotConflict(IDgraphClient client)
{
var txn1 = client.NewTransaction();
var txn2 = client.NewTransaction();
var personTxn1 = MintAPerson("Alfred Name");
var personTxn2 = MintAPerson("Fank Person");
// Name has term and exact indexes, so these shouldn't clash
var transactionResultTxn1 = await txn1.Mutate(new RequestBuilder().
WithMutations(new MutationBuilder {
SetJson = JsonConvert.SerializeObject(personTxn1)
}));
AssertResultIsSuccess(transactionResultTxn1);
personTxn1.Uid = transactionResultTxn1.Value.Uids[personTxn1.Uid.Substring(2)];
var transactionResultTxn2 = await txn2.Mutate(new RequestBuilder().
WithMutations(new MutationBuilder {
SetJson = JsonConvert.SerializeObject(personTxn2)
}));
AssertResultIsSuccess(transactionResultTxn2);
personTxn2.Uid = transactionResultTxn2.Value.Uids[personTxn2.Uid.Substring(2)];
// Can't see the other result
var queryByName = await txn2.QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", personTxn1.Name }
});
AssertResultIsSuccess(queryByName);
queryByName.Value.Json.Should().Be("{\"q\":[]}");
// Cause the mutates can't clash these should be ok
AssertResultIsSuccess(await txn1.Commit());
AssertResultIsSuccess(await txn2.Commit());
// both are there
queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", personTxn1.Name }
});
AssertResultIsSuccess(queryByName);
FriendQueries.AssertStringIsPerson(queryByName.Value.Json, personTxn1);
queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", personTxn2.Name }
});
AssertResultIsSuccess(queryByName);
FriendQueries.AssertStringIsPerson(queryByName.Value.Json, personTxn2);
}
private async Task QueryWithVars(IDgraphClient client)
{
var queryResult = await client.QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", Person3.Name }
});
AssertResultIsSuccess(queryResult, "Query failed");
FriendQueries.AssertStringIsPerson(queryResult.Value, Person3);
}
private async Task QueryWithVars(IDgraphClient client)
{
var queryPerson = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", Person3.Name }
});
AssertResultIsSuccess(queryPerson, "Query failed");
FriendQueries.AssertStringIsPerson(queryPerson.Value.Json, Person3);
}
private async Task ConflictingTransactionsDontBothSucceed(IDgraphClient client)
{
var txn1 = client.NewTransaction();
var txn2 = client.NewTransaction();
var personTxn1 = MintAPerson("Bill Person");
var personTxn2 = MintAPerson("Jane Person");
var transactionResultTxn1 = await txn1.Mutate(new RequestBuilder().
WithMutations(new MutationBuilder {
SetJson = JsonConvert.SerializeObject(personTxn1)
}));
AssertResultIsSuccess(transactionResultTxn1);
personTxn1.Uid = transactionResultTxn1.Value.Uids[personTxn1.Uid.Substring(2)];
var transactionResultTxn2 = await txn2.Mutate(new RequestBuilder().
WithMutations(new MutationBuilder {
SetJson = JsonConvert.SerializeObject(personTxn2)
}));
AssertResultIsSuccess(transactionResultTxn2);
// Name has term and exact indexes, so these clash on 'Person' term
AssertResultIsSuccess(await txn1.Commit());
var txn2Result = await txn2.Commit();
txn2Result.IsFailed.Should().BeTrue();
// Not 100% sure about this quirk. Pretty sure this is how is how
// dgo does it, but I wonder that it should be in an error state?
txn2.TransactionState.Should().Be(TransactionState.Committed);
// txn1 is there
var queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", personTxn1.Name }
});
AssertResultIsSuccess(queryByName);
FriendQueries.AssertStringIsPerson(queryByName.Value.Json, personTxn1);
// txn2 had no effect
queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", personTxn2.Name }
});
AssertResultIsSuccess(queryByName);
queryByName.Value.Json.Should().Be("{\"q\":[]}");
}
private async Task QueryAllThreePeople(IDgraphClient client)
{
var people = new List <Person> {
Person1, Person2, Person3
};
foreach (var person in people)
{
var queryPerson = await client.Query(FriendQueries.QueryByUid(person.Uid));
AssertResultIsSuccess(queryPerson, "Query failed");
// the query result is json like { q: [ ...Person... ] }
FriendQueries.AssertStringIsPerson(queryPerson.Value, person);
}
}
private async Task NoDirtyReads(IDgraphClient client)
{
var txn1 = client.NewTransaction();
var person = MintAPerson(nameof(NoDirtyReads));
var json = JsonConvert.SerializeObject(person);
var transactionResult = await txn1.Mutate(new RequestBuilder().
WithMutations(new MutationBuilder {
SetJson = json
}));
AssertResultIsSuccess(transactionResult, "Mutation failed");
person.Uid = transactionResult.Value.Uids[person.Uid.Substring(2)];
// Can we see this from another transaction?
var queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", person.Name }
});
AssertResultIsSuccess(queryByName);
queryByName.Value.Json.Should().Be("{\"q\":[]}");
// Can we see it in the uid (note that uid queries always return the
// uid ... we are interested if returns the actual person or not)
var queryByUid = await client.NewReadOnlyTransaction().
Query(FriendQueries.QueryByUid(person.Uid));
AssertResultIsSuccess(queryByUid);
queryByUid.Value.Json.Should().Be($"{{\"q\":[{{\"uid\":\"{person.Uid}\"}}]}}");
AssertResultIsSuccess(await txn1.Commit());
queryByName = await client.NewReadOnlyTransaction().QueryWithVars(
FriendQueries.QueryByName,
new Dictionary <string, string> {
{ "$name", person.Name }
});
AssertResultIsSuccess(queryByName);
FriendQueries.AssertStringIsPerson(queryByName.Value.Json, person);
}
private async Task DeleteAPerson(IDgraphClient client)
{
using (var transaction = client.NewTransaction()) {
// delete a node by passing JSON like this to delete
var deleteResult = await transaction.Mutate(
deleteJson : $"{{\"uid\": \"{Person1.Uid}\"}}");
AssertResultIsSuccess(deleteResult, "Delete failed");
var transactionResult = await transaction.Commit();
AssertResultIsSuccess(transactionResult);
}
// that person should be gone...
var queryPerson1 = await client.NewReadOnlyTransaction().
Query(FriendQueries.QueryByUid(Person1.Uid));
AssertResultIsSuccess(queryPerson1, "Query failed");
// no matter what uid you query for, Dgraph always succeeds :-(
// e.g. on a fresh dgraph with no uids allocated
// { q(func: uid(0x44444444)) { uid }}
// will answer
// "q": [ { "uid": "0x44444444" } ]
//
// so the only way to test that the node is deleted,
// is to test that we got only that back
queryPerson1.Value.Json.Should().Be($"{{\"q\":[{{\"uid\":\"{Person1.Uid}\"}}]}}");
// ... but watch out, Dgraph can leave dangling references
// e.g. there are some edges in our graph that still point to
// Person 1 - we've just removed all it's outgoing edges.
var queryPerson3 = await client.NewReadOnlyTransaction().
Query(FriendQueries.QueryByUid(Person3.Uid));
AssertResultIsSuccess(queryPerson3, "Query failed");
var person3 = JObject.Parse(queryPerson3.Value.Json)["q"][0].ToObject <Person>();
person3.Friends.Count.Should().Be(2);
}
private async Task DeleteAPerson(IDgraphClient client)
{
using (var transaction = client.NewTransaction()) {
// delete a node by passing JSON like this to delete
var deleteResult = await transaction.Delete($"{{\"uid\": \"{Person1.Uid}\"}}");
AssertResultIsSuccess(deleteResult, "Delete failed");
await transaction.Commit();
}
// that person should be gone...
var queryPerson1 = await client.Query(FriendQueries.QueryByUid(Person1.Uid));
AssertResultIsSuccess(queryPerson1, "Query failed");
// no matter what uid you query for, Dgraph always succeeds :-(
// e.g. on a fresh dgraph with no uids allocated
// { q(func: uid(0x44444444)) { uid }}
// will answer
// "q": [ { "uid": "0x44444444" } ]
//
// so the only way to test that the node is deleted,
// is to test that we got only that back
queryPerson1.Value.Should().Be($"{{\"q\":[{{\"uid\":\"{Person1.Uid}\"}}]}}");
// -----------------------------------------------------------
// ... but watch out, Dgraph can leave dangling references :-(
// -----------------------------------------------------------
var queryPerson3 = await client.Query(FriendQueries.QueryByUid(Person3.Uid));
AssertResultIsSuccess(queryPerson3, "Query failed");
var person3 = JObject.Parse(queryPerson3.Value) ["q"][0].ToObject <Person>();
person3.Friends.Count.Should().Be(2);
// You'll need something like GraphSchema to handle things like
// cascading deletes etc. and clean up automatically :-)
}
