cannot convert 'bytes' object to str implicitly

Question

I am trying to open a gif file, and send its bytes properly to a webbrowser but it throws the exception 'cannot convert 'bytes' object to str implicitly' and frankly I am baffled, because I already converted it to a string.

files=open("WebContent/"+fileName,"rb")
#size=os.path.getsize("WebContent/"+fileName)
text=str(files.read())
text=text.encode('UTF-8')
defaultResponseCode="HTTP/1.1 200 OK\r\nContent-Type: image/gif\r\nContent-Transfer-Encoding: binary\r\nContent-Length: 29696\r\n\r\n"+text

Thanks in advance!

Why convert to string? You don't need that. Your Content-Transfer-Encoding header claims to be "binary", hence no encoding has been applied on the data. Send the image just as you read it from the file. — Michael F
– Michael F, Commented Jan 12, 2014 at 16:01

ndpu · Accepted Answer · 2014-01-12 19:26:13Z

1

Here you are trying to convert bytes (file opened with 'rb' mode) to string:

text = str(files.read())

change above line to this:

text = files.read().decode(encoding='change_to_source_file_encoding')

then you can convert unicode string to utf-8 byte string with:

text = text.encode('UTF-8')

And if source encoding is utf-8 you can just pass byte string from files.read() to your result string without senseless decode/encode steps (from utf-8 bytes to string and again to utf-8 bytes)...

update: try with requests

url = 'url'
files = {'file': open("WebContent/"+fileName, 'rb')}
response = requests.post(url, files=files)

update 2:

According to content-type in response header (... Content-Type: image/gif ...) you have data with needed format just after files.read() whithout any encoding/decoding!

edited Jan 12, 2014 at 19:26

answered Jan 12, 2014 at 14:59

ndpu

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6 Comments

ndpu Over a year ago

@user1564622 try now, you are using python3?

Adam Smith Over a year ago

I'm confused -- you should either read this as a string and use it as a string or read it as bytes and use it as bytes. Why both?

ndpu Over a year ago

@user1564622 source file in utf-8 encoding?, try to change encoding or decoding with errors='ignore': text = files.read().decode(encoding='utf8', 'ignore')

Adam Smith Over a year ago

No I mean the methodology doesn't make sense. You've having him read a file as bytes, then decode to string based on utf-8 encoding, then re-encoding that string to bytes, then sending out. @user1564622, skip the str(files.read()) call if you only need to sent it to your browser as bytes, and just send files.read(). If you need the plaintext string, save it to a different variable instead using files.read.decode(encoding='utf8') as ndpu suggested.

user1564622 Over a year ago

OK, bottom line, can someone show me read a file and send it correctly in http

|

philwalk · Accepted Answer · 2014-05-12 21:13:59Z

0

For those primarily interested in Popen rather than psql, here's a debugged working python3 script, based the original Popen question, and incorporating provided suggestions.

#!/usr/bin/env python3

# print a list of postgresql databases via psql
import subprocess

username = "postgres"
dbname = "postgres"

p = subprocess.Popen(
  args = ['psql', '-qAt', '-U', username, '-d', dbname],
# args = ['psql', '-qAt', '-d', dbname], # with adequate user permissions
  stdin = subprocess.PIPE,
  stdout = subprocess.PIPE
)
sql = b"SELECT datname FROM pg_database;"

dbs = p.communicate(b"SELECT datname FROM pg_database;")[0].split(b'\n')

for db in dbs:
  print("%s" % db.decode("utf-8"))

p.wait()

answered May 12, 2014 at 21:13

philwalk

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Comments

jpaugh · Accepted Answer · 2017-08-10 18:42:08Z

0

In python 3+ I was getting similar problem, and I removed text.encode("utf-8") and used text.strip().

text = text.strip()

edited Aug 10, 2017 at 18:42

jpaugh

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answered Aug 10, 2017 at 18:06

Nitish K.

11 bronze badge

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