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#!/usr/bin/python3
import sys, re, sqlite3, json
from http.server import HTTPServer, BaseHTTPRequestHandler
import urllib.parse
hostname = "localhost"
port = 8000
dbFile = "data/data.db"
tolnodeReqDepth = 1
# For a /node?name=name1 request, respond with name1's node, and descendent nodes in a subtree to some depth > 0
usageInfo = f"usage: {sys.argv[0]}\n"
usageInfo += "Starts a server that listens for GET requests to http://" + hostname + ":" + str(port) + ".\n"
usageInfo += "Responds to path+query /data/type1?name=name1 with JSON data.\n"
usageInfo += "\n"
usageInfo += "If type1 is 'node': \n"
usageInfo += " Responds with a map from names to node objects, representing\n"
usageInfo += " nodes name1, and child nodes up to depth " + str(tolnodeReqDepth) + ".\n"
usageInfo += "If type1 is 'children': Like 'node', but excludes node name1.\n"
usageInfo += "If type1 is 'chain': Like 'node', but gets nodes from name1 up to the root, and their direct children.\n"
usageInfo += "If type1 is 'search': Responds with a tolnode name that has alt-name name1, or null.\n"
dbCon = sqlite3.connect(dbFile)
def lookupNode(name):
cur = dbCon.cursor()
cur.execute("SELECT name, data FROM nodes WHERE name = ?", (name,))
row = cur.fetchone()
return row[1] if row != None else None
def lookupName(name):
cur = dbCon.cursor()
cur.execute("SELECT name, alt_name FROM names WHERE alt_name = ?", (name,))
row = cur.fetchone()
return json.dumps(row[0]) if row != None else None
class DbServer(BaseHTTPRequestHandler):
def do_GET(self):
# Parse URL
urlParts = urllib.parse.urlparse(self.path)
path = urllib.parse.unquote(urlParts.path)
queryDict = urllib.parse.parse_qs(urlParts.query)
# Check first element of path
match = re.match(r"/([^/]+)/(.+)", path)
if match != None and match.group(1) == "data" and "name" in queryDict:
reqType = match.group(2)
name = queryDict["name"][0]
print(name)
# Check query string
if reqType == "node":
nodeJson = lookupNode(name)
if nodeJson != None:
results = []
getResultsUntilDepth(name, nodeJson, tolnodeReqDepth, results)
self.respondJson(nodeResultsToJSON(results))
return
elif reqType == "children":
nodeJson = lookupNode(name)
if nodeJson != None:
obj = json.loads(nodeJson)
results = []
for childName in obj["children"]:
nodeJson = lookupNode(childName)
if nodeJson != None:
getResultsUntilDepth(childName, nodeJson, tolnodeReqDepth, results)
self.respondJson(nodeResultsToJSON(results))
return
elif reqType == "chain":
results = []
ranOnce = False
while True:
jsonResult = lookupNode(name)
if jsonResult == None:
if ranOnce:
print("ERROR: Parent-chain node {} not found".format(name), file=sys.stderr)
break
results.append([name, jsonResult])
obj = json.loads(jsonResult)
# Add children
if not ranOnce:
ranOnce = True
else:
internalFail = False
for childName in obj["children"]:
jsonResult = lookupNode(childName)
if jsonResult == None:
print("ERROR: Parent-chain-child node {} not found".format(name), file=sys.stderr)
internalFail = True
break
results.append([childName, jsonResult])
if internalFail:
break
# Check if root
if obj["parent"] == None:
self.respondJson(nodeResultsToJSON(results))
return
else:
name = obj["parent"]
elif reqType == "search":
nameJson = lookupName(name)
if nameJson != None:
self.respondJson(nameJson)
return
self.send_response(404)
self.end_headers()
self.end_headers()
def respondJson(self, jsonStr):
self.send_response(200)
self.send_header("Content-type", "application/json")
self.end_headers()
self.wfile.write(jsonStr.encode("utf-8"))
def getResultsUntilDepth(name, nodeJson, depth, results):
"""Given a node [name, nodeJson] pair, adds child node pairs to 'results', up until 'depth'"""
results.append([name, nodeJson])
if depth > 0:
obj = json.loads(nodeJson)
for childName in obj["children"]:
childJson = lookupNode(childName)
if childJson != None:
getResultsUntilDepth(childName, childJson, depth-1, results)
def nodeResultsToJSON(results):
"""Given a list of [name, nodeJson] pairs, returns a representative JSON string"""
jsonStr = "{"
for i in range(len(results)):
jsonStr += json.dumps(results[i][0]) + ":" + results[i][1]
if i < len(results) - 1:
jsonStr += ","
jsonStr += "}"
return jsonStr
server = HTTPServer((hostname, port), DbServer)
print("Server started at http://{}:{}".format(hostname, port))
try:
server.serve_forever()
except KeyboardInterrupt:
pass
server.server_close()
dbCon.close()
print("Server stopped")
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