问题
This is my first question.
I am having users upload their own image to a database. That image is stored as a BLOB.
I was able to do this successfully. I am using MySQL for the database.
The part I am having trouble with is displaying that BLOB as an image on the website when its called upon.
Right now only the Binary data, lots of weird symbols are being displayed. I think its a problem with the HTTP header. Right now its in :
print "Content-Type: text/html"
I've tried:
print "Content-Type: image/jpeg"
I am using Python to connect with the database and write the HTML.
Edit: Code:
def showFile():
# do SQL to retrieve blob where filename
conn, cursor = getConnectionAndCursor()
sql = """
select data
from upload
where id=1
"""
cursor.execute(sql)
data = cursor.fetchone()
blob = data[0]
print "<hr>"
print "This is what I'm trying"
print """<img src="data:image/jpeg;base64,%s/>""" % data
######################################################################
if __name__ == "__main__":
form = cgi.FieldStorage()
if "show_file" in form:
print "Content-Type: text/html"
print
printHeaders("Image upload example")
showFile()
printFooter()
回答1:
image is stored in database in binary format so once it comes to server using decode function to get it back to image
image.decode('base64')
this will convert your blob to image
回答2:
Depending on how its encoded, you can also possibly just use a Data URI for the image. Something like this might work if they are encoded as base64 PNGs.
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIA..." />
As @Alok says, you might need to first convert it from binary blob to base64, then use the Data URI.
回答3:
Well, you can either return an HTML response, and use a combination of the existing answers, or you can just return an image/jpeg response, and dump the BLOB directly to stdout, with something like this...
def showFile():
# do SQL to retrieve blob where filename
conn, cursor = getConnectionAndCursor()
sql = """
select data
from upload
where id=1
"""
cursor.execute(sql)
data = cursor.fetchone()
blob = data[0]
print blob
if __name__ == "__main__":
form = cgi.FieldStorage()
if "show_file" in form:
print "Content-Type: image/jpeg"
print
showFile()
...but it depends on what you're trying to achieve.
来源：https://stackoverflow.com/questions/16279856/converting-blob-stored-on-a-database-to-an-image-on-an-html-website