Zig

Firebase GET - Reading Data

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Demonstrates how to read parts of a Firebase JSON database. The data used in this example is at Chilkat Firebase Pigs Database, and is shown here:

Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // Demonstrates how to read parts of a Firebase JSON database.

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // This example assumes a JWT authentication token, if required, has been previously obtained.
    // See Get Firebase Access Token from JSON Service Account Private Key for sample code.

    // Load the previously obtained Firebase access token into a string.
    const fac = try chilkat.FileAccess.init();
    defer fac.deinit();
    const access_token = fac.readEntireTextFile(alloc, "qa_data/tokens/firebaseToken.txt", "utf-8") catch {
        std.debug.print("{s}\n", .{try fac.getLastErrorText(alloc)});
        return;
    };

    const rest = try chilkat.Rest.init();
    defer rest.deinit();

    // Make the initial connection (without sending a request yet).
    // Once connected, any number of requests may be sent.  It is not necessary to explicitly
    // call Connect before each request.
    rest.connect("chilkat.firebaseio.com", 443, true, true) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // If authentication is required...
    const auth_google = try chilkat.AuthGoogle.init();
    defer auth_google.deinit();
    auth_google.setAccessToken(access_token);
    rest.setAuthGoogle(auth_google) catch {};

    // Chilkat's sample data (pig-rescue data) is publicly readable at: https://chilkat.firebaseio.com/.json

    // Let's get the animals with the shallow parameter so we can see how many pigs exist.
    const json_response = rest.fullRequestNoBody(alloc, "GET", "/pig-rescue/animal.json?shallow=true") catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // The JSON returned should look like this:
    // {"-KI3bD-FU_Dake7sYOiP":true,"-KI3bD-FU_Dake7sYOiT":true,"-KI3bD-FU_Dake7sYOiS":true,"-KI3bD-FU_Dake7sYOiU":true,"-KI3bD-FU_Dake7sYOiV":true,"-KI3bD-FU_Dake7sYOiR":true,"-KI3bD-FU_Dake7sYOiQ":true}
    std.debug.print("{s}\n", .{json_response});

    // Parse the response so we can iterate over each pig in the database..
    const piggy_path = try chilkat.StringBuilder.init();
    defer piggy_path.deinit();
    const shallow = try chilkat.JsonObject.init();
    defer shallow.deinit();
    const piggy_data = try chilkat.JsonObject.init();
    defer piggy_data.deinit();
    shallow.load(json_response) catch {};
    const count = shallow.getSize();
    var i: i32 = 0;
    while (i < count) {
        // Get each individual pig's data.
        piggy_path.clear();
        piggy_path.append("/pig-rescue/animal/") catch {};
        piggy_path.append(try shallow.nameAt(alloc, i)) catch {};
        piggy_path.append("/.json") catch {};

        const piggy_json = rest.fullRequestNoBody(alloc, "GET", try piggy_path.getAsString(alloc)) catch {
            std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
            return;
        };

        // Show this piggy's data...
        // An example of one pig's data is shown here:
        // {"birth":"February, 1998","from":"Middle Ave.","gender":"F","in-date":"January, 2000",
        //   "name":"Molly II","picture":{"caption":"Molly in the Pasture","description":"Black pig","file":"molly_th.jpg"},
        //   "species":"pot belly pig","type":"Cathy's Herd"}
        std.debug.print("---- {d} ----\n", .{i});
        std.debug.print("{s}\n", .{piggy_json});

        // Let's get the pig's name, and the caption of the picture.
        piggy_data.load(piggy_json) catch {};
        std.debug.print("name: {s}\n", .{try piggy_data.stringOf(alloc, "name")});
        std.debug.print("caption: {s}\n", .{try piggy_data.stringOf(alloc, "picture.caption")});

        i = i + 1;
    }

    // Note: In many of the Chilkat examples, you may notice strange ways
    // of doing something that should be simpler and shorter.  For example,
    // building the piggyPath (above) could've been written differently,
    // with some simple string concatenation.
    //
    // The reason is that the Chilkat examples are written in a
    // proprietary "example code" scripting language,
    // and then automatically generated to each of the different programming
    // languages you see on example-code.com.  The code generation is
    // limited in what it can do.  For example, string concatentation
    // is not yet a feature of the "example code" scripting language (as of May 2016),
    // and therefore you won't see the use of a programming language's string
    // concatentation operators in any example.
    //
}