How to save firebase storage downloadURL to firestore collection?

Question

I'm unable to save my firebase storage image into a firestore collection variable. It was working fine for some time but then stopped working. The image variable returns null.

ps - I'm using the asia-south1 server

Here's my template code for ManageProducts

<div>
      <h1>Add Items</h1>
      <div>
        <form>
          <input type="text" placeholder="name" required v-model="item.name" />
          <textarea
            required
            placeholder="description"
            v-model="item.description"
          ></textarea>
          <input
            type="text"
            required
            placeholder="price"
            v-model="item.price"
          />
          <div class="form-group">
            <input
              type="text"
              placeholder="Available/Unavailable"
              v-model.lazy="item.status"
              class="form-control"
            />
          </div>
          <div class="form-group">
            <input
              type="text"
              placeholder="Sewing Partner"
              v-model.lazy="item.sewingPartner"
              class="form-control"
            />
          </div>
          <input type="file" required @change="uploadImage" accept="image/*" />
          <button @click.prevent="AddNewItem">Add Item</button> |
          <button class="delete">
            Cancel
          </button>
        </form>
      </div>

Here's the script for Manage Products. In here, I'm able to add all the other input values except for the firebase storage's image Url.

  <script>
    import { dbItemAdd } from "../../main";
    import firebase from "firebase";
    import "firebase/firestore";
    import "firebase/storage";
    export default {
      name: "AddItems",
      components: { AdminPreviewItems },
      data() {
        return {
          items: [],
          item: {
            name: null,
            description: null,
            image: null,
            price: null,
            status: null,
            sewingPartner: null,
          },
        };
      },
      methods: {
        uploadImage(e) {
          let file = e.target.files[0];
          var storageRef = firebase.storage().ref("products/" + file.name);
          let uploadTask = storageRef.put(file);
          uploadTask.on(
            "state_changed",
            (snapshot) => {
              console.log(snapshot);
            },
            (error) => {
              // Handle unsuccessful uploads
              console.log(error.message);
            },
            () => {
              // Handle successful uploads on complete
              // For instance, get the download URL: https://firebasestorage.googleapis.com/...
              uploadTask.snapshot.ref.getDownloadURL().then((downloadURL) => {
                this.item.image = downloadURL;
                console.log("File available at", downloadURL);
              });
            }
          );
        },
    
        AddNewItem() {
          dbItemAdd
            .add({
              name: this.item.name,
              description: this.item.description,
              image: this.item.image,
              price: this.item.price,
              status: this.item.status,
              sewingPartner: this.item.sewingPartner,
            })
            .then(() => {
              location.reload();
              console.log("Adding data to Firestore");
            })
            .catch((error) => {
              console.error("Error adding document: ", error);
            });
        },
      },
    };
    </script>

Answer 1

When are you calling the AddNewItem function? If the image is not uploaded yet or the downloadURL is not fetched, if you click the submit button it'll be null.

uploadTask.snapshot.ref.getDownloadURL().then((downloadURL) => {
  this.item.image = downloadURL;
  console.log("File available at", downloadURL);
  //function must be called after this
});

You can disable the submit button is this.item.image is null (default value).

<button :disabled="!item.image" @click.prevent="AddNewItem">Add Item</button>

I don't see state_changed observer being used. Do you need to show the upload progress? If yes, keep the existing code as it is else I would refactor it as an async function like this:

async uploadImage(e) {
  let file = e.target.files[0];
  if (!file) alert("No file selected")
  var storageRef = firebase.storage().ref("products/" + file.name);
  let uploadTask = await storageRef.put(file);
  const url = await storageRef.getDownloadURL()
  this.item.image = url
}

You are actually uploading the image on file change and not submit button click so you could add the Firestore document from the @change event itself right after getting downloadURL.

Answer 2

Once you upload a file to storage, you call the getDownloadURL() which will generate an access token

You then store this URL and access token directly into firestore

// Create reference to image
var mountainImagesRef = storageRef.child('images/mountains.jpg');
// Put image file to Storage
ref.put(file).then((snapshot) => {
// On complete, get the downloadURL
return mountainImagesRef.getDownloadURL()})
.then((downloadURL) =>
// Add download URL to Firestore
firestore().doc("path/to/document/here").add({
              name: this.item.name,
              description: this.item.description,
              image: downloadURL,
              price: this.item.price,
              status: this.item.status,
              sewingPartner: this.item.sewingPartner,})
).catch(console.error);