How do I read large amounts of CGI data via POST in Rebol3?

Question

I'm trying to upload an image using POST. Then on the server to get the POST data, I use:

data: read system/ports/input

...but it seems that the data is truncated.

There doesn't seem to be some specific boundary where the data are truncated. I'm uploading images in range from cca 15-200kB, and the resulting data are few hundreds to few tens of kB long, so there's no artificial boundary like 32'000 bytes.

Does anyone have experience with getting data from POST?

@rebolek I saw your question in the chat room and decided to answer it here. I'm a brand new user and have no access to chat. — Dan Lee, Sep 17 '14 at 22:48
thanks to your fantastic response now you have enough reputation to participate in chat :) — rebolek, Sep 18 '14 at 05:40

score 4 · Answer 1 · answered Sep 17 '14 at 22:42

4

The read action on system/ports/input works at a low level, like a stream. Continuous reads will return partial data until the end of input is reached. The problem is that system/ports/input will return an error at the end of input instead of none! or an empty string.

The following code works for me to read large POST input:

image: make binary! 200'000
while [
    not error? try [data: read system/ports/input]
][
        append image data
]

answered Sep 17 '14 at 22:42

Dan Lee

71
5

Thanks! I'm going to try it. – rebolek Sep 18 '14 at 05:37
So I've tried it and unfortunately, I have different experience. READ on `system/ports/input` doesn't throw an error but is stuck waiting for data and does not timeout. – rebolek Sep 18 '14 at 06:01
What version and what OS do you use? I got an empty string at the end; see below. – sqlab Sep 19 '14 at 06:39
I'm using the latest Atronix 64-bit build on Windows 7 Pro with Apache 2.4.3.0 (32-bit). I noticed that the standard input port behaves differently on the command line that it does in CGI. On the command line, I can read continuously without getting an error. – Dan Lee Sep 20 '14 at 13:43

sqlab · Answer 2 · 2014-09-19T06:37:42.907

1

with r3-64-view-2014-02-14-1926d8.exe I used

while [
    all [
       not error? try [data: read system/ports/input]
       0 < probe length? data
    ]
][
    append image data
]
print length? image

And did

D:\own\Rebol>r3-64-view-2014-02-14-1926d8.exe read-img.r < r3-64-view-2014-02-14-1926d8.exe > err.txt

and got

edited Sep 19 '14 at 06:37

answered Sep 18 '14 at 12:03

sqlab

6,412
1
14
29

Can't find that build, but I tried the [latest Atronix Windows 64-bit build](http://atronixengineering.com/r3/downloads/r3-64-view.exe) on Windows 7 Professional and Apache v2.4.3.0 (32-bit). This combination works for me. – Dan Lee Sep 18 '14 at 17:06

How do I read large amounts of CGI data via POST in Rebol3?

2 Answers2