def start(self):
# Open connection to proxy
try:
proxy_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
proxy_sock.connect((self.proxy_host, self.proxy_port))
print("Connected to socket")
except OSError as e:
print("Unable to connect to socket: ", message)
if proxy_sock:
proxy_sock.close()
sys.exit(1)
# Send requested URL to proxy
str_url = self.url
[hostname, pathname] = http_util.parse_url(str_url)
str_req = http_util.create_http_req(hostname, pathname)
bin_req = str_req.encode('utf-8')
proxy_sock.sendall(bin_req)
# Receive binary data from proxy
bin_reply = b''
while True:
more = proxy_sock.recv(4096)
if not more:
break
bin_reply += more
print('Client received from proxy (showing 1st 300 bytes): ',
bin_reply)
# Close connection to proxy
proxy_sock.close()
def serve_content(self, conn, addr):
# Receive binary request from client
bin_req = conn.recv(4096)
try:
str_req = bin_req.decode('utf-8')
print(str_req)
except ValueError as e:
print("Unable to decode request, not utf-8", e)
conn.close()
return
# Extract host and path
hostname = http_util.get_http_field(str_req, 'Host: ', const.END_LINE)
pathname = http_util.get_http_field(str_req, 'GET ', ' HTTP/1.1')
if hostname == -1 or pathname == -1:
print("Cannot determine host")
client_conn.close()
return
elif pathname[0] != '/':
[hostname, pathname] = http_util.parse_url(pathname)
str_req = http_util.create_http_req(hostname, pathname)
url = hostname + pathname
# add to cache if not present, append cached date to modify request if applicable
if url in self.proxy_cache:
print(
'********************** URL in the cache already... ********************** '
)
[temp_response, temp_date] = self.proxy_cache[url]
print("Printing cached response: ", temp_response)
print("Printing cached date: ", temp_date)
new_string_req = http_util.add_http_field(str_req,
"If-Modified-Since",
str(temp_date))
print(
'********************** String request updated:******************* '
)
print(new_string_req)
str_req = new_string_req
bin_req = str_req.encode('utf-8')
# Open connection to host and send binary request
try:
web_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
web_sock.connect((hostname, 80))
print(
"********************** Sending request to web server ********************** "
)
print("Request: ", str_req)
web_sock.sendall(bin_req)
except OSError as e:
print("Unable to open web socket: ", e)
if web_sock:
web_sock.close()
conn.close()
return
# Wait for response from web server
bin_reply = b''
while True:
more = web_sock.recv(4096)
if not more:
break
bin_reply += more
# Find the date element from the response
print(
'********************** Decoding and date extraction ********************** '
)
try:
response = bin_reply.decode('utf-8')
try:
date = http_util.get_http_field(response, "Last-Modified: ",
const.END_LINE)
print(date)
except:
date = http_util.get_http_field(response, "Date: ",
const.END_LINE)
print(date)
except ValueError as e:
print("ERROR: Unable to decode URL object: ", e)
# isolate response code
code = http_util.get_http_field(response, "HTTP/1.1 ", const.END_LINE)
print(
'********************** HTTP Code extraction ********************** '
)
print('Code: ', code)
# Implement caching
if code == "304 Not Modified":
# send encoded cached response
reply = self.proxy_cache[url][0].encode(
'utf-8') # format in dict: cache[url] = [response, date]
print(
'********************** Response received, no modifications... ********************** '
)
print('Cached response: ', reply[:300])
conn.sendall(reply)
print('Came from the cache!')
# Close connection to client
conn.close()
elif code == "200 OK": # when it HAS been modified
# update cache
self.proxy_cache[url] = [response, date]
reply = response
print(
'********************** Response received from server... ********************** '
)
print('Cache updated, showing 1st 300 bytes...')
print('Response: ', reply[:300])
conn.sendall(bin_reply)
print('Came from updated response!')
# Close connection to client
conn.close()
else: # Some error with the response code or request
print("Problem with request... closing connection")
conn.close()
def serve_content(self, conn, addr):
# Receive binary request from client
bin_req = conn.recv(4096)
try:
str_req = bin_req.decode('utf-8')
print(str_req)
except ValueError as e:
print ("Unable to decode request, not utf-8", e)
conn.close()
return
# Extract host and path
hostname = http_util.get_http_field(str_req, 'Host: ', const.END_LINE)
pathname = http_util.get_http_field(str_req, 'GET ', ' HTTP/1.1')
if hostname == -1 or pathname == -1:
print ("Cannot determine host")
client_conn.close()
return
elif pathname[0] != '/':
[hostname, pathname] = http_util.parse_url(pathname)
str_req = http_util.create_http_req(hostname, pathname)
url = hostname + pathname
#-----------------------------My Code----------------------------------------
#Checks if url is in the cache and if is, save to keyVal
if(url in self.cache):
print("url is in cache")
cache_temp = self.cache[url]
add_date = cache_temp[0]
new_str_req = http_util.add_http_field(str_req, "If-Modified-Since", str(add_date))
str_req = new_str_req
#Check the cache contents
# Open connection to host and send binary request
bin_req = str_req.encode('utf-8')
try:
web_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
web_sock.connect((hostname, 80))
print ("Sending request to web server: ", str_req)
web_sock.sendall(bin_req)
except OSError as e:
print ("Unable to open web socket: ", e)
if web_sock:
web_sock.close()
conn.close()
return
# Wait for response from web server
bin_reply = b''
while True:
more = web_sock.recv(4096)
if not more:
break
bin_reply += more
#-------Decode here----------
try:
decoded = bin_reply.decode('utf-8')
try:
date = http_util.get_http_field(decoded, "Last-Modified: ","\r\n")
except:
date = http_util.get_http_field(decoded, "Date: ", "\r\n")
except ValueError as e:
print("Unable to Decode Url Object", e)
#Proxy now Checks Server Response
#-----if there is no modification to dict---
if(http_util.get_http_field(decoded, "HTTP/1.1 ", "\r\n") == "304 Not Modified"):
print("Server sent back 304 Not Modified.")
#Update cache to not modified...
conn.sendall(self.cache[url][1])
print("Came from the Cache, 304 Not Modified")
#---------if server returns 200 OK--------
elif(http_util.get_http_field(decoded, "HTTP/1.1 ", "\r\n") == "200 OK"):
self.cache[url] = [date,bin_reply]
print('Proxy received from server (showing 1st 300 bytes): ', bin_reply[:300])
conn.sendall(bin_reply)
#----------if there is some kind of error----
else: #if there is a problem
print("Error with Request, Closing connection.")
conn.close()
#---------Close connection to client------
conn.close()