Upload files to OSS directly from a client

let credentials = null;
const form = document.querySelector("form");
form.addEventListener("submit", async (event) => {
  event.preventDefault();
  // To reduce calls to the STS service, retrieve credentials again only when the current ones expire.
  if (isCredentialsExpired(credentials)) {
    const response = await fetch("/get_sts_token_for_oss_upload", {
      method: "GET",
    });
    if (!response.ok) {
      // Handle the error HTTP status code.
      throw new Error(
        `Failed to obtain STS token: ${response.status} ${response.statusText}`
      );
    }
    credentials = await response.json();
  }
  const client = new OSS({
    // Set <YOUR_BUCKET> to your OSS bucket name.
    bucket: "<YOUR_BUCKET>",
    // Set <YOUR_REGION> to the region where the OSS bucket is located, for example, region: 'oss-cn-hangzhou'.
    region: "oss-<YOUR_REGION>",
    accessKeyId: credentials.AccessKeyId,
    accessKeySecret: credentials.AccessKeySecret,
    stsToken: credentials.SecurityToken,
  });

  const fileInput = document.querySelector("#file");
  const file = fileInput.files[0];
  const result = await client.put(file.name, file);
  console.log(result);
});

/**
 * Check whether the temporary credentials have expired.
 **/
function isCredentialsExpired(credentials) {
  if (!credentials) {
    return true;
  }
  const expireDate = new Date(credentials.Expiration);
  const now = new Date();
  // If the validity period is less than one minute, the credentials are considered expired.
  return expireDate.getTime() - now.getTime() <= 60000;
}

const form = document.querySelector("form");
const fileInput = document.querySelector("#file");
form.addEventListener("submit", (event) => {
  event.preventDefault();
  const file = fileInput.files[0];
  if (!fileInput.files[0]) {
    alert('Please select a file to upload.');
    return;
  }
  const filename = fileInput.files[0].name;
  fetch("/get_post_signature_for_oss_upload", { method: "GET" })
    .then((response) => {
      if (!response.ok) {
        throw new Error("Failed to obtain the signature.");
      }
      return response.json();
    })
    .then((data) => {
      const formData = new FormData();
      formData.append("name", filename);
      formData.append("policy", data.policy);
      formData.append("OSSAccessKeyId", data.ossAccessKeyId);
      formData.append("success_action_status", "200");
      formData.append("signature", data.signature);
      formData.append("key", data.dir + filename);
      formData.append("file", file);

      return fetch(data.host, { method: "POST", body: formData });
    })
    .then((response) => {
      if (response.ok) {
        console.log("Upload successful");
        alert("File uploaded.");
      } else {
        console.log("Upload failed", response);
        alert("Upload failed. Please try again later.");
      }
    })
    .catch((error) => {
      console.error("An error occurred:", error);
    });
});

const form = document.querySelector("form");
form.addEventListener("submit", (event) => {
  event.preventDefault();
  const fileInput = document.querySelector("#file");
  const file = fileInput.files[0];
  fetch("/get_presigned_url_for_oss_upload", { method: "GET" })
    .then((response) => {
      if (!response.ok) {
        throw new Error("Failed to obtain the presigned URL.");
      }
      return response.text();
    })
    .then((url) => {
      fetch(url, {
        method: "PUT",
        headers: new Headers({
          "Content-Type": "image/png",
        }),
        body: file,
      }).then((response) => {
        if (!response.ok) {
          throw new Error("Failed to upload the file to OSS.");
        }
        console.log(response);
        alert("File uploaded.");
      });
    })
    .catch((error) => {
      console.error("An error occurred:", error);
      alert(error.message);
    });
});