# Example: demonstrates TCP/IP TXMODE via HTTP POST of an image """ HTTP POST DEMO USING Python TCPIP TX MODE ========================================= This script demonstrates how TCPIP TX MODE can be used to send images to a server via HTTPS. The demonstration also shows how additional header information can be generated, in this case the current battery voltage. The demo requires a FAT32 formatted SD Card to be inserted in to the X-Link in order to hold the image. The script will generate an HTTP header for a multipart POST in order to send the image file. The script will also generate some HTTP content that includes the name of the file. Below is an example of the HTTP header and body generated by the script. In this example, the 'image' file is really a text file with only this data: 1234567890 POST /post HTTP/1.1 Host: httpbin.org Content-Type: multipart/form-data; boundary=Start-OttHydromet-Boundary-End Content-Length: 182 Battery-Voltage: 10.75 --Start-OttHydromet-Boundary-End Content-Disposition: form-data; name="file"; filename="test_image.jpg" Content-Type: image/jpeg 1234567890 --Start-OttHydromet-Boundary-End-- If you are using a version of LinkComm which will not let you set the TXMODE to Python TCPIP (but are running a version of firmware that supports it) you will need to click the "Test Script File..." button and the script will set the necessary fields. If you need to change the setup after that, be sure to click "Test Script File..." button again. The demo will transmit any files in the /sd/tx1 folder. If you would like to create a fake image to send then run the script task create_image. The public test server httpbin.org is used to perform the test transmission and verify the result. The last result can be displayed by running the script task display_results. With the following TX1 setup, this script will transmit any images in the /sd/tx1 folder to httpbin.org test server every hour via secure HTTPS:: !TX1 Enable=On !TX1 Radio Type=Cell !TX1 Kind=Scheduled !TX1 Label=HTTP POST !TX1 Scheduled Interval=01:00:00 !TX1 Scheduled Time=00:00:00 !TX1 Data Source=File !TX1 Max Files Per Tx=16 !TX1 File Expiry Period=10080 min !TX1 Mode=Python TCPIP !TX1 Secure=On !TX1 Use Certificate=Off !TX1 Mode Function=send_image_http !TX1 Main Server=httpbin.org !TX1 Backup Server= !TX1 Server Port=443 !TX1 Server Username= !TX1 Server Password= !TX1 Server Path=post You can attempt the transmission with HTTP rather than secure HTTPS by setting the following (not all modems support HTTPS):: !TX1 Secure=Off !TX1 Server Port=80 """ from sl3 import * from os import stat, urandom last_results = "No results so far" def receive_data(socket, amount=1024, iterations=120): """ Receive data from a socket. This function calls socket.recv(amount) up to 'iterations' times, concatenating and returning the result. It exits early if after receiving data on one iteration it doesn't receive data on the next. :param socket: The socket object to receive data from. :type socket: socket.socket :param amount: The maximum amount of data to be received at once, defaults to 1024. :type amount: int, optional :param iterations: The maximum number of iterations to attempt receiving data, defaults to 10. :type iterations: int, optional :return: The concatenated data received from the socket. :rtype: bytes """ result = b'' data_received = False for _ in range(iterations): data = socket.recv(amount) if data: result += data data_received = True elif data_received: break else: data_received = False return result @TXMODE def send_image_http(socket, message, file_name): """ Function to send an image file via HTTP POST to httpbin.org. :param socket: Open socket for sending/receiving data. :param message: Unused (we expect a file transfer) :param file_name: Name of the file to be sent ('image.jpg' in this case). :return: 0 if HTTP POST was accepted and acknowledged, 1 if there was an issue. """ global last_results if is_being_tested(): print("This function cannot be tested due to file usage and server reply") return 1 if file_name is None: last_results = "Expected file tranmission" print(last_results) return 1 # do not retry CRLF = '\r\n' last_results = "Sending file " + file_name try: # Prepare the HTTP POST request headers file_size = stat(file_name)[6] if file_size == 0: last_results = "File does not exist or is 0 bytes " & file_name print(last_results) return 0 # do not retry boundary = 'Start-OttHydromet-Boundary-End' body_start = CRLF.join([ '--{}'.format(boundary), 'Content-Disposition: form-data; name="file"; filename="{}"'.format(file_name.split('/')[-1]), 'Content-Type: image/jpeg', '', '', ]) body_end = CRLF.join([ '', '--{}--'.format(boundary), '', ]) content_length = len(body_start) + file_size + len(body_end) path = setup_read("!TX{} Server Path".format(index())) host = setup_read("!TX{} Main Server".format(index())) headers = [ 'POST /{} HTTP/1.1'.format(path), 'Host: httpbin.org', 'Content-Type: multipart/form-data; boundary={}'.format(boundary), 'Content-Length: {}'.format(content_length), ] # Custom header entries can go here (it's easiest to avoid spaces in the field names): custom_headers = [ 'Battery-Voltage: {:.2f}'.format(batt()), ] # Concatenate all headers into a single byte string headers_data = CRLF.join(headers) + CRLF + CRLF.join(custom_headers) + 2*CRLF last_results = "Sending headers" print("Header:") print(headers_data) # Send the headers and start of the body socket.send(headers_data + body_start) last_results = "Sending file data" # Send the file data in 1KB chunks with open(file_name, 'rb') as file: while True: chunk = file.read(1024) # Read in chunks to conserve memory if not chunk: break socket.send(chunk) # Send the end of the body socket.send(body_end) # Set a timeout for receiving the HTTP response # please note that we are already connected to the server # so this is the timeout for server to reply to the POST socket.settimeout(3) # Timeout seconds last_results = "Receiving reply" # Receive the HTTP response, allowing up to 30 seconds response = receive_data(socket) if len(response) == 0: response = "".encode('utf-8') last_results = "Server Response:\r\n" + response.decode('utf-8') print(last_results) # Check if the server acknowledged the message if b'HTTP/1.1 200 OK' in response or b'HTTP/1.0 200 OK' in response: return 0 # HTTP POST accepted and acknowledged else: return 1 # Server did not acknowledge properly except Exception as e: last_results = "Transmission failed due to " + str(e) print(last_results) return 1 # Error occurred, do not retry @TASK def create_image(): """ Create a fake image to send on the SD card. Set the `simple` variable in the function to True if you want a small 10 byte image, or to False if you want an image consisting of 16KB of random data. """ if not is_being_tested(): simple = True with open("/sd/TX1/test_image.jpg", "wb") as f: if simple: f.write("1234567890") else: # create a 16KB test image of random data for i in range(16): f.write(urandom(1024)) print("Test image has been created.") @TASK def display_results(): """ Display the last results received from the HTTP Server """ global last_results print("Last results:") print(last_results) # in case version of LinkComm is being used which can't set these fields, we'll set them for it if setup_read("tx1 label") == "HTTP POST": if setup_read("tx1 mode") != "Python TCPIP": setup_write("tx1 mode", "Python TCPIP") if setup_read("tx1 mode function") != "send_image_http": setup_write("tx1 mode function", "send_image_http")