Execute workflow for callback app

Web app to support a translation workflow that waits for human input and uses callback endpoints.

Explore further

For detailed documentation that includes this code sample, see the following:

• Create a human-in-the-loop workflow using callbacks

Code sample

Node.js

Before trying this sample, follow the Node.js setup instructions in the Workflows quickstart using client libraries. For more information, see the Workflows Node.js API reference documentation.

To authenticate to Workflows, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

document.addEventListener("DOMContentLoaded", async function (event) {
    const textArea = document.getElementById("text");
    textArea.focus();

    const newBtn = document.getElementById("newBtn");
    newBtn.addEventListener("sl-focus", event => {
        event.target.blur();
        window.location.reload();
    });

    const translationAlert = document.getElementById("translation");
    const buttonRow = document.getElementById("buttonRow");

    var callbackUrl = "";

    const validationAlert = document.getElementById("validationAlert");
    const rejectionAlert = document.getElementById("rejectionAlert");
    const validateBtn = document.getElementById("validateBtn");
    const rejectBtn = document.getElementById("rejectBtn");

    const translateBtn = document.getElementById("translateBtn");
    translateBtn.addEventListener("sl-focus", async event => {
        event.target.disabled = true;
        event.target.loading = true;
        textArea.disabled = true;

        console.log("Text to translate = ", textArea.value);

        const fnUrl = UPDATE_ME;

        try {
            console.log("Calling workflow executor function...");
            const resp = await fetch(fnUrl, {
                method: "POST",
                headers: {
                    "accept": "application/json",
                    "content-type": "application/json"
                },
                body: JSON.stringify({ text: textArea.value })
            });
            const executionResp = await resp.json();
            const executionId = executionResp.executionId.slice(-36);
            console.log("Execution ID = ", executionId);

            const db = firebase.firestore();
            const translationDoc = db.collection("translations").doc(executionId);

            var translationReceived = false;
            var callbackReceived =  false;
            var approvalReceived = false;
            translationDoc.onSnapshot((doc) => {
                console.log("Firestore update", doc.data());
                if (doc.data()) {
                    if ("translation" in doc.data()) {
                        if (!translationReceived) {
                            console.log("Translation = ", doc.data().translation);
                            translationReceived = true;
                            translationAlert.innerText = doc.data().translation;
                            translationAlert.open = true;
                        }
                    }
                    if ("callback" in doc.data()) {
                        if (!callbackReceived) {
                            console.log("Callback URL = ", doc.data().callback);
                            callbackReceived = true;
                            callbackUrl = doc.data().callback;
                            buttonRow.style.display = "block";
                        }
                    }
                    if ("approved" in doc.data()) {
                        if (!approvalReceived) {
                            const approved = doc.data().approved;
                            console.log("Approval received = ", approved);
                            if (approved) {
                                validationAlert.open = true;
                                buttonRow.style.display = "none";
                                newBtn.style.display = "inline-block";   
                            } else {
                                rejectionAlert.open = true;
                                buttonRow.style.display = "none";
                                newBtn.style.display = "inline-block";
                            }
                            approvalReceived = true;
                        }
                    }
                }
            });
        } catch (e) {
            console.log(e);
        }
        event.target.loading = false;
    });

    validateBtn.addEventListener("sl-focus", async event => {
        validateBtn.disabled = true;
        rejectBtn.disabled = true;
        validateBtn.loading = true;
        validateBtn.blur();

        // call callback
        await callCallbackUrl(callbackUrl, true);
    });

    rejectBtn.addEventListener("sl-focus", async event => {
        rejectBtn.disabled = true;
        validateBtn.disabled = true;
        rejectBtn.loading = true;
        rejectBtn.blur();

        // call callback
        await callCallbackUrl(callbackUrl, false);
    });

});

async function callCallbackUrl(url, approved) {
    console.log("Calling callback URL with status = ", approved);

    const fnUrl = UPDATE_ME;
    try {
        const resp = await fetch(fnUrl, {
            method: "POST",
            headers: {
                "accept": "application/json",
                "content-type": "application/json"
            },
            body: JSON.stringify({ url, approved })
        });
        const result = await resp.json();
        console.log("Callback answer = ", result);
    } catch(e) {
        console.log(e);
    }
}

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.