如何在Python中启动Bloomberg API？已装blpapi但会话启动失败求助

Hey there! Let's walk through how to get the Bloomberg API up and running in Python, and fix that frustrating "failed to start session" error you're encountering.

First, let's cover the foundational requirements since the API relies heavily on your Bloomberg Terminal setup:

• Active Terminal Session: You must have a logged-in Bloomberg Terminal running on your machine. The API communicates directly with the terminal process, so no terminal = no connection.
• API Access Enabled: Open your terminal, type API <GO>, and make sure the option "Allow Bloomberg API clients to access this Bloomberg Terminal" is checked. Without this, the API can't establish a session.
• Compatible Dependencies: You've already installed blpapi, but ensure it's compatible with the tia library you're using. Version mismatches are a common culprit—run this to lock in a known working set:

  pip install --upgrade blpapi==3.20.3 tia==0.2.19
  

That exception almost always ties back to one of these issues:

• Terminal Not Running/API Access Disabled: Double-check the terminal is logged in and the API access toggle is on (via API <GO>).
• Port Conflict: The Bloomberg API uses port 8194 by default. Verify this port isn't being used by another app, and confirm the port number in your terminal's API settings matches.
• Automatic Session Setup Failures: The tia.BbgDataManager tries to auto-create a session under the hood, but sometimes manual initialization is more reliable (we'll cover this next).

Instead of letting tia handle session setup automatically, manually initialize a blpapi.Session first to confirm connectivity, then pass it to the data manager:

import blpapi
import pandas as pd
import tia.bbg.datamgr as dm

# Step 1: Manually initialize and test the blpapi session
session_options = blpapi.SessionOptions()
session_options.setServerHost('localhost')
session_options.setServerPort(8194)

session = blpapi.Session(session_options)
if not session.start():
    raise Exception("Failed to connect to Bloomberg Terminal - check terminal login and API settings")

# Step 2: Use the working session with tia's data manager
mgr = dm.BbgDataManager(session)

# Step 3: Run your historical data request as before
sids = mgr['MSFT US EQUITY', 'IBM US EQUITY', 'CSCO US EQUITY']
df = sids.get_historical('PX_LAST', '1/1/2014', '11/12/2014')
print(df.head())

# Clean up the session when done (good practice)
session.stop()

If you want to bypass tia and use the raw blpapi for more control, here's a quick example of fetching historical data directly:

import blpapi

# Initialize session
session_options = blpapi.SessionOptions()
session_options.setServerHost('localhost')
session_options.setServerPort(8194)

session = blpapi.Session(session_options)
if not session.start():
    print("Failed to start Bloomberg session")
    exit(1)

# Build historical data request
request = session.createRequest("HistoricalDataRequest")
request.getElement("securities").appendValue("MSFT US EQUITY")
request.getElement("securities").appendValue("IBM US EQUITY")
request.getElement("fields").appendValue("PX_LAST")
request.set("startDate", "20140101")
request.set("endDate", "20141112")

# Send request and process responses
session.sendRequest(request)
while True:
    event = session.nextEvent()
    for msg in event:
        if event.eventType() in (blpapi.Event.RESPONSE, blpapi.Event.PARTIAL_RESPONSE):
            security_data = msg.getElement("securityData")
            ticker = security_data.getElement("security").getValue()
            print(f"\nData for {ticker}:")
            for entry in security_data.getElement("fieldData").values():
                date = entry.getElement("date").getValue()
                close_price = entry.getElement("PX_LAST").getValue()
                print(f"{date}: {close_price}")
    if event.eventType() == blpapi.Event.RESPONSE:
        break

# Close the session
session.stop()

内容的提问来源于stack exchange，提问作者Hannah Lee