b2_upload_file

Uploads one file to B2, returning its unique file ID.

Warning: Do not include Protected Health Information (PHI) or Personally Identifiable Information (PII) in bucket names, object/file/folder names, or other metadata. Such metadata is not encrypted in a way that meets Health Insurance Portability and Accountability Act (HIPAA) protection requirements for PHI/PII data and is not generally encrypted in client-side encryption architectures.

Request

The upload request is a POST. The file name and other parameters are in the request headers, and the file to be uploaded is the request body.

URL Path

Use the b2_get_upload_url operation to get a URL you can use to upload files. The URL it returns will contain your bucket ID and the upload destination, and will look something like this:

https://pod-000-1007-13.backblaze.com/b2api/v2/b2_upload_file/4a48fe8875c6214145260818/c001_v0001007_t0042

Request HTTP Headers

Authorization

required

An upload authorization token, from b2_get_upload_url. The token must have the writeFiles capability.

X-Bz-File-Name

required

The name of the file, in percent-encoded UTF-8. For example, spaces should be replaced with %20. For more information, see Files for requirements on file names and String Encoding for how to encode strings.

Content-Type

required

The MIME type of the content of the file, which will be returned in the Content-Type header when downloading the file. Use the Content-Type b2/x-auto to automatically set the stored Content-Type post upload. In the case where a file extension is absent or the lookup fails, the Content-Type is set to application/octet-stream. The Content-Type mappings can be perused here.

Content-Length

required

The number of bytes in the file being uploaded. Note that this header is required; you cannot leave it out and just use chunked encoding.
When sending the SHA1 checksum at the end, the Content-Length should be set to the size of the file plus the 40 bytes of hex checksum.

X-Bz-Content-Sha1

required

The SHA1 checksum of the content of the file. B2 will check this when the file is uploaded, to make sure that the file arrived correctly. It will be returned in the X-Bz-Content-Sha1 header when the file is downloaded.
You may optionally provide the SHA1 at the end of the upload. See the section on Uploading.

X-Bz-Info-src_last_modified_millis

optional

If the original source of the file being uploaded has a last modified time concept, Backblaze recommends using this spelling of one of your X-Bz-Info-* headers (see below). Using a standard spelling allows different B2 clients and the B2 web user interface to interoperate correctly. The value should be a base 10 number which represents a UTC time when the original source file was last modified. It is a base 10 number of milliseconds since midnight, January 1, 1970 UTC. This fits in a 64 bit integer such as the type "long" in the programming language Java. It is intended to be compatible with Java's time long. For example, it can be passed directly into the Java call Date.setTime(long time).

X-Bz-Info-b2-content-disposition

optional

If this is present, B2 will use it as the value of the 'Content-Disposition' header when the file is downloaded (unless it's overridden by a value given in the download request). The value must match the grammar specified in RFC 6266. Parameter continuations are not supported. 'Extended-value's are supported for charset 'UTF-8' (case-insensitive) when the language is empty. Note that this file info will not be included in downloads as a x-bz-info-b2-content-disposition header. Instead, it (or the value specified in a request) will be in the Content-Disposition.

X-Bz-Info-b2-content-language

optional

If this is present, B2 will use it as the value of the 'Content-Language' header when the file is downloaded (unless it's overridden by a value given in the download request). The value must match the grammar specified in RFC 2616. Note that this file info will not be included in downloads as a x-bz-info-b2-content-language header. Instead, it (or the value specified in a request) will be in the Content-Language header.

X-Bz-Info-b2-expires

optional

If this is present, B2 will use it as the value of the 'Expires' header when the file is downloaded (unless it's overridden by a value given in the download request). The value must match the grammar specified in RFC 2616. Note that this file info will not be included in downloads as a x-bz-info-b2-expires header. Instead, it (or the value specified in a request) will be in the Expires header.

X-Bz-Info-b2-cache-control

optional

If this is present, B2 will use it as the value of the 'Cache-Control' header when the file is downloaded (unless it's overridden by a value given in the download request), and overriding the value defined at the bucket level. The value must match the grammar specified in RFC 2616. Note that this file info will not be included in downloads as a x-bz-info-cache-control header. Instead, it (or the value specified in a request) will be in the Cache-Control header.

X-Bz-Info-b2-content-encoding

optional

If this is present, B2 will use it as the value of the 'Content-Encoding' header when the file is downloaded (unless it's overridden by a value given in the download request). The value must match the grammar specified in RFC 2616. Note that this file info will not be included in downloads as a x-bz-info-b2-content-encoding header. Instead, it (or the value specified in a request) will be in the Content-Encoding header.

X-Bz-Info-*

optional

The * part of the header name is replaced with the name of a custom field in the file information stored with the file, and the value is an arbitrary UTF-8 string, percent-encoded. The same info headers sent with the upload will be returned with the download. The header name is case insensitive.

X-Bz-Custom-Upload-Timestamp

optional

If this is present, B2 will use it as the value of the upload timestamp. The value should be a base 10 number that represents a UTC time when the original source file was uploaded. It is a base 10 number of milliseconds since midnight, January 1st, 1970 UTC. This fits in a 64-bit integer, such as the type long in Java, and so it can be passed directly into the Java call Date.setTime(long time). The value must not use a date that is set to a time in the future.
NOTE: If you need to use this feature, please contact Backblaze support to have the feature enabled on your account.

X-Bz-File-Legal-Hold

optional

If this is present, specifies the Object Lock legal hold status for the file. Valid values for this header are on and off. Setting the value requires the writeFileLegalHolds capability and that the bucket is Object Lock-enabled.

X-Bz-File-Retention-Mode

optional

If this is present, specifies the Object Lock retention mode for the file. Valid values for this header are governance and compliance. Setting the value requires the writeFileRetentions capability and that the bucket is Object Lock-enabled.
If this header is present, then a valid X-Bz-File-Retention-Retain-Until-Timestamp header must be present as well.

X-Bz-File-Retention-Retain-Until-Timestamp

optional

If this is present, specifies a Object Lock retention timestamp in the future, after which the intended Object Lock will expire. This header value must be specified as a base 10 number of milliseconds since midnight, January 1, 1970 UTC. Setting the value requires the writeFileRetentions capability and that the bucket is Object Lock-enabled.
If this header is present, then a valid X-Bz-File-Retention-Mode header must be present as well.

X-Bz-Server-Side-Encryption

optional

If this is present, B2 will encrypt the uploaded data before storing the file using Server-Side Encryption with Backblaze-Managed Keys (SSE-B2) with the algorithm specified in this header. Currently, the only supported value for this header is AES256.
This header must not be present if SSE-C headers (X-Bz-Server-Side-Encryption-Customer-*, see below) are included with this request, and vice versa.

X-Bz-Server-Side-Encryption-Customer-Algorithm

optional

If this is present, B2 will encrypt the uploaded data before storing the file using Server-Side Encryption with Customer-Managed Keys (SSE-C) with the algorithm specified in this header. Currently, the only supported value for this header is AES256.

X-Bz-Server-Side-Encryption-Customer-Key

optional

If this is present, it specifies the base64-encoded encryption key for Backblaze B2 to use in encrypting data with Server-Side Encryption with Customer-Managed Keys (SSE-C). The value of the header is used to store the file and then is immediately discarded. The key must be appropriate for use with the algorithm specified in the X-Bz-Server-Side-Encryption-Customer-Algorithm header.

X-Bz-Server-Side-Encryption-Customer-Key-Md5

optional

If this is present, it specifies the base64-encoded 128-bit MD5 digest of the encryption key to be used with Server-Side Encryption with Customer-Managed Keys (SSE-C). Backblaze B2 uses this header to verify that the encryption key was transmitted correctly.

The following HTTP headers must not be included in the b2_upload_file request:

The file name and file info must fit within a 7,000 byte limit. For files that are uploaded with Server-Side Encryption and/or to Object Lock-enabled buckets, the size limit is reduced to 2,048 bytes. See Files for further details about HTTP header size limit.

Request HTTP Message Body Parameters

There are no JSON parameters allowed. The file to be uploaded is the message body and is not encoded in any way. It is not URL encoded. It is not MIME encoded.

Response

Response HTTP Status 200

File successfully uploaded. The JSON response will contain the standard file information. For uploaded files, the action is always "upload".

accountId

The account that owns the file.

action

One of "start", "upload", "hide", "folder", or other values added in the future. "upload" means a file that was uploaded to B2 Cloud Storage. "start" means that a large file has been started, but not finished or canceled. "hide" means a file version marking the file as hidden, so that it will not show up in b2_list_file_names. "folder" is used to indicate a virtual folder when listing files.

bucketId

The bucket that the file is in.

contentLength

The number of bytes stored in the file. Only useful when the action is "upload". Always 0 when the action is "start", "hide", or "folder".

contentSha1

The SHA1 of the bytes stored in the file as a 40-digit hex string. Large files do not have SHA1 checksums, and the value is "none". The value is null when the action is "hide" or "folder".

contentMd5

optional

The MD5 of the bytes stored in the file as a 32-digit hex string. Not all files have an MD5 checksum, so this field is optional, and set to null for files that do not have one. Large files do not have MD5 checksums, and the value is null. The value is also null when the action is "hide" or "folder".

contentType

When the action is "upload" or "start", the MIME type of the file, as specified when the file was uploaded. For "hide" action, always "application/x-bz-hide-marker". For "folder" action, always null.

fileId

The unique identifier for this version of this file. Used with b2_get_file_info, b2_download_file_by_id, and b2_delete_file_version. The value is null when for action "folder".

fileInfo

The custom information that was uploaded with the file. This is a JSON object, holding the name/value pairs that were uploaded with the file.

fileName

The name of this file, which can be used with b2_download_file_by_name.

fileRetention

The Object Lock retention settings for this file, if any.
This field is filtered based on application key capabilities; the readFileRetentions capability is required to access the value. See Object Lock for more details on response structure.
This field is omitted when the action is "hide" or "folder".

legalHold

The Object Lock legal hold status for this file, if any.
This field is filtered based on application key capabilities; the readFileLegalHolds capability is required to access the value. See Object Lock for more details on response structure.
This field is omitted when the action is "hide" or "folder".

replicationStatus

The Replication Status for this file, if any. This will show either PENDING, COMPLETED, FAILED, or REPLICA. For details see Cloud Replication
This field is omitted when the file is not part of a replication rule.

serverSideEncryption

When the file is encrypted with Server-Side Encryption, the mode ("SSE-B2" or "SSE-C") and algorithm used to encrypt the data. If the file is not encrypted with Server-Side Encryption, then both mode and algorithm will be null.
This field is omitted when the action is "hide" or "folder".

uploadTimestamp

This is a UTC time when this file was uploaded. It is a base 10 number of milliseconds since midnight, January 1, 1970 UTC. This fits in a 64 bit integer such as the type "long" in the programming language Java. It is intended to be compatible with Java's time long. For example, it can be passed directly into the java call Date.setTime(long time).
Always 0 when the action is "folder".

Response Errors

File not uploaded. If possible the server will return a JSON error structure. Errors include:

status

code

description

400

auth_token_limit

The auth token is already being used. For more information, see Uploading in Parallel.

400

bad_bucket_id

The requested bucket ID does not match an existing bucket.

400

bad_request

The request had the wrong fields or illegal values. The message returned with the error will describe the problem.

400

cannot_delete_non_empty_bucket

A bucket must be empty before it can be deleted. To delete this bucket, first remove all of the files in the bucket, then try the delete operation again.

400

custom_timestamp_invalid

The request has an invalid custom upload timestamp.

400

custom_timestamp_not_allowed

The account is not allowed to specify a custom upload timestamp.

401

unauthorized

The auth token used is valid, but does not authorize this call with these parameters. The capabilities of an auth token are determined by the application key used with b2_authorize_account.

401

bad_auth_token

The auth token used is not valid. Call b2_get_upload_url again to get a new one.

401

expired_auth_token

The auth token used has expired. Call b2_get_upload_url again to get a new one.

403

cap_exceeded

Usage cap exceeded.

405

method_not_allowed

Only POST is supported

408

request_timeout

The service timed out reading the uploaded file

503

service_unavailable

Call b2_get_upload_url again to get a new auth token.

Some errors returned mean that you must call b2_get_upload_url again to get a new upload URL and authorization token. See Uploading for details.

API Versions

v1: Application keys (July 26, 2018)

Incompatible change: After calling b2_authorize_account with an application key that does not have the right permissions, this call will return a 401 Unauthorized.

v1: Original release (September 22, 2015)

Sample Code

Code

FILE_TO_UPLOAD=typing_test.txt
MIME_TYPE=text/plain
SHA1_OF_FILE=$(openssl dgst -sha1 $FILE_TO_UPLOAD | awk '{print $2;}')
UPLOAD_URL=... # from b2_get_upload_url call
UPLOAD_AUTHORIZATION_TOKEN=... # from b2_get_upload_url call

curl \
    -H "Authorization: $UPLOAD_AUTHORIZATION_TOKEN" \
    -H "X-Bz-File-Name: $FILE_TO_UPLOAD" \
    -H "Content-Type: $MIME_TYPE" \
    -H "X-Bz-Content-Sha1: $SHA1_OF_FILE" \
    -H "X-Bz-Info-Author: unknown" \
    -H "X-Bz-Server-Side-Encryption: AES256" \
    --data-binary "@$FILE_TO_UPLOAD" \
    $UPLOAD_URL

Output

{
    "fileId" : "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName" : "typing_test.txt",
    "accountId" : "12f634bf3cbz",
    "bucketId" : "4a48fe8875c6214145260818",
    "contentLength" : 46,
    "contentSha1" : "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType" : "text/plain",
    "fileInfo" : {
       "author" : "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption" : {
       "algorithm" : "AES256",
       "mode" : "SSE-B2"
    }
}

Code

import java.io.*;
import java.util.*;
import javax.json.*;
import java.net.HttpURLConnection;
import java.net.URL;

String uploadUrl = ""; // Provided by b2_get_upload_url
String uploadAuthorizationToken = ""; // Provided by b2_get_upload_url
String fileName = "typing_test.txt"; // The name of the file you are uploading
String contentType = "text/plain"; // The content type of the file
String sha1 = "bae5ed658ab3546aee12f23f36392f35dba1ebdd"; // SHA1 of the file you are uploading
byte[] fileData;
HttpURLConnection connection = null;
String json = null;
try {
    URL url = new URL(uploadUrl);
    connection = (HttpURLConnection)url.openConnection();
    connection.setRequestMethod("POST");
    connection.setRequestProperty("Authorization", uploadAuthorizationToken);
    connection.setRequestProperty("Content-Type", contentType);
    connection.setRequestProperty("X-Bz-File-Name", fileName);
    connection.setRequestProperty("X-Bz-Content-Sha1", sha1);
    connection.setRequestProperty("X-Bz-Info-Author", "unknown");
    connection.setRequestProperty("X-Bz-Server-Side-Encryption", "AES256");
    connection.setDoOutput(true);
    DataOutputStream writer = new DataOutputStream(connection.getOutputStream());
    writer.write(fileData);
    String jsonResponse = myInputStreamReader(connection.getInputStream());
    System.out.println(jsonResponse);
} catch (Exception e) {
    e.printStackTrace();
} finally {
    connection.disconnect();
}

static public String myInputStreamReader(InputStream in) throws IOException {
    InputStreamReader reader = new InputStreamReader(in);
    StringBuilder sb = new StringBuilder();
    int c = reader.read();
    while (c != -1) {
        sb.append((char)c);
        c = reader.read();
    }
    reader.close();
    return sb.toString();
}

Output

{
    "fileId" : "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName" : "typing_test.txt",
    "accountId" : "12f634bf3cbz",
    "bucketId" : "4a48fe8875c6214145260818",
    "contentLength" : 46,
    "contentSha1" : "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType" : "text/plain",
    "fileInfo" : {
       "author" : "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption" : {
       "algorithm" : "AES256",
       "mode" : "SSE-B2"
    }
}

Code

import json
import urllib2
import hashlib

upload_url = "" # Provided by b2_get_upload_url
upload_authorization_token = "" # Provided by b2_get_upload_url
file_data = "Now, I am become Death, the destroyer of worlds."
file_name = "typing_test.txt"
content_type = "text/plain"
sha1_of_file_data = hashlib.sha1(file_data).hexdigest()

headers = {
    'Authorization' : upload_authorization_token,
    'X-Bz-File-Name' :  file_name,
    'Content-Type' : content_type,
    'X-Bz-Content-Sha1' : sha1_of_file_data,
    'X-Bz-Info-Author' : 'unknown',
    'X-Bz-Server-Side-Encryption' : 'AES256'
    }
request = urllib2.Request(upload_url, file_data, headers)

response = urllib2.urlopen(request)
response_data = json.loads(response.read())
response.close()

Output

{
    "fileId" : "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName" : "typing_test.txt",
    "accountId" : "12f634bf3cbz",
    "bucketId" : "4a48fe8875c6214145260818",
    "contentLength" : 46,
    "contentSha1" : "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType" : "text/plain",
    "fileInfo" : {
       "author" : "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption" : {
       "algorithm" : "AES256",
       "mode" : "SSE-B2"
    }
}

Code

import Foundation

let uploadUrl = "" // Provided by b2_get_upload_url
let uploadAuthorizationToken = "" // Provided by b2_get_upload_url
let fileName = "typing_test.txt" // The name of the file you are uploading
let contentType = "text/plain" // The content type of the file
let sha1 = "bae5ed658ab3546aee12f23f36392f35dba1ebdd" // SHA1 of the file you are uploading

var fileData: Data?
do {
	// Read file into memory
	let fileData = try Data(contentsOf: URL(fileURLWithPath: "<path_to_a_file>"))
} catch (let error) {
	print("\(error.localizedDescription)")
}
	
// Create request
var request = URLRequest(url: uploadUrl)
request.httpMethod = "POST"
request.addValue(uploadAuthorizationToken, forHTTPHeaderField: "Authorization")
request.addValue(fileName, forHTTPHeaderField: "X-Bz-File-Name")
request.addValue(contentType, forHTTPHeaderField: "Content-Type")
request.addValue(sha1, forHTTPHeaderField: "X-Bz-Content-Sha1")
request.addValue("unknown", forHTTPHeaderField: "X-Bz-Info-Author")
request.addValue("AES256", forHTTPHeaderField: "X-Bz-Server-Side-Encryption")

// Create task
let task = URLSession.shared.uploadTask(with: request, from: fileData) { (data, response, error) in
	if let data = data {
		let json = String(data: data, encoding: .utf8)
		print("\(json!)")
	}
}

// Start task
task.resume()

// Swift 4.1 (swiftlang-902.0.48 clang-902.0.37.1) Xcode 9.3.1 (9E501)

Output

{
    "fileId": "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName": "typing_test.txt",
    "accountId": "12f634bf3cbz",
    "bucketId": "4a48fe8875c6214145260818",
    "contentLength": 46,
    "contentSha1": "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType": "text/plain",
    "fileInfo": {
       "author": "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption": {
       "algorithm": "AES256",
       "mode": "SSE-B2"
    }
}

Code

require 'json'
require 'net/http'
require 'digest/sha1'

upload_url = "" # Provided by b2_get_upload_url
local_file = "" # File to be uploaded
upload_authorization_token = "" # Provided by b2_get_upload_url
file_name = "typing_test.txt" # The name of the file you are uploading
content_type = "text/plain"  # The content type of the file
sha1 = "bae5ed658ab3546aee12f23f36392f35dba1ebdd" # SHA1 of the file you are uploading
uri = URI(upload_url)
req = Net::HTTP::Post.new(uri)
req.add_field("Authorization","#{upload_authorization_token}")
req.add_field("X-Bz-File-Name","#{file_name}")
req.add_field("Content-Type","#{content_type}")
req.add_field("X-Bz-Content-Sha1","#{sha1}")
req.add_field("Content-Length",File.size(local_file))
req.add_field("X-Bz-Info-Author","unknown")
req.add_field("X-Bz-Server-Side-Encryption","AES256")
req.body = File.read(local_file)
http = Net::HTTP.new(req.uri.host, req.uri.port)
http.use_ssl = (req.uri.scheme == 'https')
res = http.start {|http| http.request(req)}
case res
when Net::HTTPSuccess then
    res.body
when Net::HTTPRedirection then
    fetch(res['location'], limit - 1)
else
    res.error!
end

Output

{
    "fileId": "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName": "typing_test.txt",
    "accountId": "12f634bf3cbz",
    "bucketId": "4a48fe8875c6214145260818",
    "contentLength": 46,
    "contentSha1": "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType": "text/plain",
    "fileInfo": {
       "author": "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption": {
       "algorithm": "AES256",
       "mode": "SSE-B2"
    }
}

Code

using System;
using System.Net;
using System.Text;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Security.Cryptography;

String uploadAuthorizationToken = "UPLOAD_AUTHORIZATION_TOKEN"; //Provided by b2_get_upload_url
String contentType = "text/plain"; //Type of file i.e. image/jpeg, audio/mpeg...
String filePath = "FILE_PATH"; //File path of desired upload 
String fileName = "typing_test.txt"; //Desired name for the file
String sha1Str = ""; //Sha1 verification for the file

// Read the file into memory and take a sha1 of the data.
FileInfo fileInfo = new FileInfo(filePath);
byte[] bytes = File.ReadAllBytes(filePath);
SHA1 sha1 = SHA1.Create();
// NOTE: Loss of precision. You may need to change this code if the file size is larger than 32-bits.
byte[] hashData = sha1.ComputeHash(bytes, 0, (int)fileInfo.Length);
StringBuilder sb = new StringBuilder();
foreach (byte b in hashData)
{
	sb.Append(b.ToString("x2"));
}
sha1Str = sb.ToString();

// Send over the wire
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(uploadUrl);
webRequest.Method = "POST";
webRequest.Headers.Add("Authorization", uploadAuthorizationToken);
webRequest.Headers.Add("X-Bz-File-Name", fileName);
webRequest.Headers.Add("X-Bz-Content-Sha1", sha1Str);
webRequest.Headers.Add("X-Bz-Info-Author", "unknown");
webRequest.Headers.Add("X-Bz-Server-Side-Encryption", "AES256");
webRequest.ContentType = contentType;
using (var stream = webRequest.GetRequestStream())
{
	stream.Write(bytes, 0, bytes.Length);
	stream.Close();
}
WebResponse response = (HttpWebResponse)webRequest.GetResponse();
var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
response.Close();
Console.WriteLine(responseString);

Output

{
    "fileId" : "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName" : "typing_test.txt",
    "accountId" : "12f634bf3cbz",
    "bucketId" : "4a48fe8875c6214145260818",
    "contentLength" : 46,
    "contentSha1" : "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType" : "text/plain",
    "fileInfo" : {
       "author" : "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption" : {
       "algorithm" : "AES256",
       "mode" : "SSE-B2"
    }
}

Code

$file_name = "typing_test.txt";
$my_file = "<path-to-file>" . $file_name;
$handle = fopen($my_file, 'r');
$read_file = fread($handle,filesize($my_file));

$upload_url = ""; // Provided by b2_get_upload_url
$upload_auth_token = ""; // Provided by b2_get_upload_url
$bucket_id = "";  // The ID of the bucket
$content_type = "text/plain";
$sha1_of_file_data = sha1_file($my_file);

$session = curl_init($upload_url);

// Add read file as post field
curl_setopt($session, CURLOPT_POSTFIELDS, $read_file); 

// Add headers
$headers = array();
$headers[] = "Authorization: " . $upload_auth_token;
$headers[] = "X-Bz-File-Name: " . $file_name;
$headers[] = "Content-Type: " . $content_type;
$headers[] = "X-Bz-Content-Sha1: " . $sha1_of_file_data;
$headers[] = "X-Bz-Info-Author: " . "unknown";
$headers[] = "X-Bz-Server-Side-Encryption: " . "AES256";
curl_setopt($session, CURLOPT_HTTPHEADER, $headers); 

curl_setopt($session, CURLOPT_POST, true); // HTTP POST
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);  // Receive server response
$server_output = curl_exec($session); // Let's do this!
curl_close ($session); // Clean up
echo ($server_output); // Tell me about the rabbits, George!

Output

{
    "fileId" : "4_h4a48fe8875c6214145260818_f000000000000472a_d20140104_m032022_c001_v0000123_t0104",
    "fileName" : "typing_test.txt",
    "accountId" : "12f634bf3cbz",
    "bucketId" : "4a48fe8875c6214145260818",
    "contentLength" : 46,
    "contentSha1" : "bae5ed658ab3546aee12f23f36392f35dba1ebdd",
    "contentType" : "text/plain",
    "fileInfo" : {
       "author" : "unknown"
    },
    "fileRetention": {
      "isClientAuthorizedToRead": true,
      "value": {
        "mode": null,
        "retainUntilTimestamp": null
      }
    },
    "legalHold": {
      "isClientAuthorizedToRead": true,
      "value": null
    },
    "serverSideEncryption" : {
       "algorithm" : "AES256",
       "mode" : "SSE-B2"
    }
}