conductor-worker-python/pyexecplugins/HttpBridge.py

import requests
import json
import logging
from datetime import datetime
from pyexecplugins.pyexecplugins import PyExecPlugin

class Plugin(PyExecPlugin):
    name = "HttpBridge"
    
    taskdef = {
        "name" : "pyrestbridge",
        "description" : "Make a Request to an endpoint and directly stream result to another endpoint. endpoint1 and endpoint2 inputs are JSON objects containing the same keys as PyRest tasks. endpoint1 and endpoint2 outputs contain status, reason and headers of the respective endpoints. Method defaults to GET for endpoint 1 and to POST for endpoint2. Content-type for endpoint2 request will be forwarded from endpoint1 Accepts if present. If fail is set to false the operation will return as completed but will carry error information.",
        "inputKeys" : ["endpoint1", "endpoint2", "fail"],
        "outputKeys" : ["endpoint1", "endpoint2"],
        "ownerEmail" : "m.lettere@gmail.com"
    }
    
    def __init__(self, data, config=None):
        super().__init__(data, config)
        self.ep1 = {}
        self.ep2 = {}
        logging.getLogger("pyexec").debug("%s", data)
        self.ep1["method"] = data.get("endpoint1").get("method") or "get"
        self.ep1["url"] = data.get("endpoint1").get("url")
        self.ep1["headers"] = data.get("endpoint1").get("headers") or {}
        self.ep1["body"] = data.get("endpoint1").get("body")
        self.ep1["params"] = data.get("endpoint1").get("params")
        self.ep1["files"] = data.get("endpoint1").get("files")
        self.ep1["expect"] = data.get("endpoint1").get("expect")
                
        self.datamap = data.get("datamap") or { "place" : "body" }
                
        self.ep2["method"] = data.get("endpoint2").get("method") or "post"
        self.ep2["url"] = data.get("endpoint2").get("url")
        self.ep2["headers"] = data.get("endpoint2").get("headers") or {}
        self.ep2["body"] = data.get("endpoint2").get("body")
        self.ep2["params"] = data.get("endpoint2").get("params")
        self.ep2["files"] = data.get("endpoint2").get("files")
        self.ep2["expect"] = data.get("endpoint2").get("expect")

        self.fail = data.get("fail") != False
                
    def doRequest1(self):
        self.session = requests.Session()
        ep = self.ep1
        logging.getLogger("pyexec").debug("%s - %s", ep["method"], ep["url"])
        self.request1 = requests.Request(ep["method"], ep["url"], headers=ep["headers"], data = ep["body"], params = ep["params"]).prepare()
        self.response1 = self.session.send(self.request1, stream=True)
        self.content_type = self.response1.headers["Content-type"]
        return self.response1
    
    def doRequest2(self):
        ep = self.ep2
        logging.getLogger("pyexec").debug("Entering request2 %s - %s", ep["method"], ep["url"])
        
        if self.datamap["place"] == "body":
        	self.request2 = requests.Request(ep["method"], ep["url"], headers=ep["headers"], data = self.response1.content).prepare()
        elif self.datamap["place"] == "params":
        	params = self.ep2["params"] or {}
        	params[self.datamap["name"]] = self.response1.content
        	self.request2 = requests.Request(ep["method"], ep["url"], headers=ep["headers"], params = params).prepare()
        	params.pop(self.datamap["name"])
        elif self.datamap["place"] == "files":
                #encode custom multipart in order to exploit streaming
                files = self.ep2["files"] or {}
                logging.getLogger("pyexec").debug("Files are - %s", files)
                headers = ep["headers"]
                headers["Content-Type"] = "multipart/form-data; boundary=PYRESTBRIDGE_BOUNDARY"
                boundary_line = "--PYRESTBRIDGE_BOUNDARY"
                prolog = ""
                for k in files:
                    prolog += boundary_line + "\r\n"
                    prolog += 'Content-Disposition: form-data; name="%s"' % k + "\r\n\r\n"
                    prolog += files[k] + "\r\n"

                prolog += boundary_line + "\r\n"
                prolog += 'Content-Disposition: form-data; name="%s"' % "file" + "\r\n"
                prolog += "Content-Type: " + self.response1.headers["Content-Type"] + "\r\n\r\n"

                epilog = "\r\n" + boundary_line + "--"
                logging.getLogger("pyexec").debug("Request2 preparing %s", files)
                self.request2 = requests.Request(ep["method"], ep["url"], headers=headers, data = self.chunkedUpload(prolog, self.response1, epilog, 1000000)).prepare()
                logging.getLogger("pyexec").debug("Request2 sending %s", datetime.now())
                
                #files[self.datamap["name"]] = (self.datamap["name"], self.response1.raw.stream())
                #m = MultipartEncoder(fields=files)
                #logging.getLogger("pyexec").debug("Files are - %s", files)
                #headers = ep["headers"]
                #headers["Content-Type"] = m.content_type
                #self.request2 = requests.Request(ep["method"], ep["url"], headers=headers, data = m).prepare()
                #self.request2 = requests.Request(ep["method"], ep["url"], headers=ep["headers"], files = files).prepare()
                #files.pop(self.datamap["name"])
        elif self.datamap["place"] == "headers":
        	headers = self.ep2["headers"] or {}
        	headers[self.datamap["name"]] = self.response1.content
        	self.request2 = requests.Request(ep["method"], ep["url"], headers=headers, data = ep["body"], params=ep["params"]).prepare()
        	
        self.response2 = self.session.send(self.request2, stream=True)
        logging.getLogger("pyexec").debug("Request2 sentg %s", datetime.now())
        self.session.close()
        return self.response2
   
    def chunkedUpload(self, prolog, response1, epilog, chunksize=1024):
        logging.getLogger("pyexec").debug("Sending prolog - %s", datetime.now())
        yield str.encode(prolog)
        logging.getLogger("pyexec").debug("Sending chunks - %s", datetime.now())
        for chunk in response1.iter_content(chunksize):
            yield chunk
        logging.getLogger("pyexec").debug("Sending epilog - %s", datetime.now())
        yield str.encode(epilog)

    def computeStatus(self, ep, response):
        if ep["expect"] == None: 
            return "COMPLETED" if response.ok else "FAILED"
        else:
            if type(ep.expect) == list:
                return "COMPLETED" if (response.status_code in ep["expect"]) else "FAILED"
            else:
                return "COMPLETED" if (response.status_code == ep["expect"]) else "FAILED"
    
    def buildOutput(self, status1, status2):
        msg = None
        hdrs1 = {}
        hdrs2 = {}
        if status1 == "FAILED":
            msg = "{} to {} failed with status {} ({}) - {}".format(self.ep1["method"], self.ep1["url"], self.response1.status_code, self.response1.reason, self.response1.text)	
            if self.fail:
                raise Exception(msg)
            else:
                return {
                    "endpoint1" : { "status" : self.response1.status_code, "reason" : self.response1.reason, "headers" : hdrs1, "error" : msg},
                    "endpoint2" : { }
                }

        elif status2 == "FAILED":
       	    msg = "{} to {} failed with status {} ({}) - {}".format(self.ep2["method"], self.ep2["url"], self.response2.status_code, self.response2.reason, self.response2.text)
            if self.fail:
                raise Exception(msg)
            else:
                return {
                    "endpoint1" : { "status" : self.response1.status_code, "reason" : self.response1.reason, "headers" : hdrs1},
                    "endpoint2" : { "status" : self.response2.status_code, "reason" : self.response2.reason, "headers" : hdrs2, "error" : msg}
                }
        else:
            return {
                "endpoint1" : { "status" : self.response1.status_code, "reason" : self.response1.reason, "headers" : hdrs1},
                "endpoint2" : { "status" : self.response2.status_code, "reason" : self.response2.reason, "headers" : hdrs2}
            }

    
    def execute(self):
        self.doRequest1()
        status1 = self.computeStatus(self.ep1, self.response1)
        status2 = "FAILED"
        if status1 == "COMPLETED":
        	self.doRequest2()
        	status2 = self.computeStatus(self.ep2, self.response2)
        return self.buildOutput(status1, status2)