Custom Fields and Queries

Custom fields and querying them is a functionality that works with Threads and Stores containers.

It allows you to define new fields by placing them in the publicMeta of a container or an object within a given container, and then querying the PrivMX Endpoint Client (using existing listing methods) for elements containing these previously defined fields.

Sample code on this page is based on the initial assumptions.

Working with Custom Fields and Queries

Below there is a simple code example of how to add a custom field to a batch of Threads, and then search for them using custom query.

Initial Setup

Let's add some required includes and initialize the PrivMX Endpoint Client with the Thread API:

// ...

#include <privmx/endpoint/core/Connection.hpp>
#include <privmx/endpoint/thread/ThreadApi.hpp>
#include <privmx/endpoint/core/Buffer.hpp>

// ...

// initialize Endpoint connection and Threads API
auto connection {core::Connection::connect(USER1_PRIVATE_KEY, SOLUTION_ID, BRIDGE_URL)};
auto threadApi {thread::ThreadApi::create(connection)};

std::vector<core::UserWithPubKey> threadUsers {
    {.userId = USER1_ID, .pubKey = USER1_PUBLIC_KEY}
};

Defining a Sample Custom Field

// ...

std::string threadCustomField = R"(
    {
        "threadType": "special"
    }
)";

// ...

Creating Threads

The following code will create a total of 6 new Threads. 3 of them will contain a Custom Field.

// ...

// Creating some ordinary Threads
for (int i = 0; i < 3; ++i) {
    threadApi.createThread(
        CONTEXT_ID, 
        threadUsers, threadUsers, 
        core::Buffer::from(""),
        core::Buffer::from("Ordinary thread")
    );
}

// Creating some Threads with the custom field
for (int i = 0; i < 3; ++i) {
    threadApi.createThread(
        CONTEXT_ID, 
        threadUsers, threadUsers, 
        core::Buffer::from(threadCustomField),
        core::Buffer::from("Thread with the custom field")
    );
}

// ...

Listing Threads

The next piece of code will demonstrate how you can filter the results of the listThreads(...) method using built-in it Custom Queries functionality to get the Threads containing the previously defined Custom Field.

// ...

// Quering over Threads
core::PagingQuery defaultListQuery = {.skip = 0, .limit = 10, .sortOrder = "desc"};
auto threadsList1 {threadApi.listThreads(CONTEXT_ID, defaultListQuery)};

core::PagingQuery customQuery = {.skip = 0, .limit = 10, .sortOrder = "desc", .queryAsJson = threadCustomField};
auto threadsList2 {threadApi.listThreads(CONTEXT_ID, customQuery)};

std::cout << "The list of all Threads:" << std::endl;
for (auto t: threadsList1.readItems) {
    std::cout << "ThreadId: " << t.threadId << " / privateMeta: " << t.privateMeta.stdString() << std::endl;
}

std::cout << "The list of Threads with the custom field:" << std::endl;
for (auto t: threadsList2.readItems) {
    std::cout << "ThreadId: " << t.threadId << " / privateMeta: " << t.privateMeta.stdString() << std::endl;
}

// ...

The results of the example above will look similar to those below:

The list of all Threads:
ThreadId: 6809fb0b57a381d1a23f10ec / privateMeta: Thread with the custom field
ThreadId: 6809fb0b57a381d1a23f10eb / privateMeta: Thread with the custom field
ThreadId: 6809fb0b57a381d1a23f10ea / privateMeta: Thread with the custom field
ThreadId: 6809fb0b57a381d1a23f10e9 / privateMeta: Ordinary thread
ThreadId: 6809fb0b57a381d1a23f10e8 / privateMeta: Ordinary thread
ThreadId: 6809fb0b57a381d1a23f10e7 / privateMeta: Ordinary thread

The list of Threads with the custom field:
ThreadId: 6809fb0b57a381d1a23f10ec / privateMeta: Thread with the custom field
ThreadId: 6809fb0b57a381d1a23f10eb / privateMeta: Thread with the custom field
ThreadId: 6809fb0b57a381d1a23f10ea / privateMeta: Thread with the custom field

A full code example can be found on Simplito's GitHub.