stdin: fix false no file test and add tests for stdin

Commit 5a14efc broke input from stdin, with the check added for
actually existing files. Add an exception when the file input is "-" so
reading from stdin works again. The original commit that introduced this
feature did not include documentation. Add documentation to "--help",
manpages and the README. Add testing for reading from stdin with python3
so future commits will not break the feature unintentionally.

Fixes: dilshod#270

README.md

@@ -38,7 +38,7 @@ pip install xlsx2csv
 ```
 **positional arguments:**
 ```
-  xlsxfile              xlsx file path
+  xlsxfile              xlsx file path, use '-' to read from STDIN
   outfile               output csv file path, or directory if -s 0 is specified
 ```
 **optional arguments:**

man/xlsx2csv.1.pod

@@ -50,6 +50,10 @@ xlsx2csv - Convert xlsx xml files to csv format
 
 The conversion uses Expat SAX parser for xml processing.
 
+=head1 STDIN
+
+Use "-" for INFILE to read from the STDIN.
+
 =head1 OPTIONS
 
 =over 4

test/run

@@ -20,15 +20,16 @@ def compare(case, arguments=[]):
         ext = "xlsx"
         if os.path.exists("test/%s.xlsm" % case):
             ext = "xlsm"
-
+        
         if os.name == 'posix':# in case of Linux
-            left = subprocess.check_output(["python%s" %pyver, "./xlsx2csv.py"] + arguments + ["test/%s.%s" %(case, ext)]).decode('utf-8').replace('\r','')
+            command = ["python%s" %pyver]
         elif os.name == 'nt':# in case of Windows
             # Use py.exe http://blog.python.org/2011/07/python-launcher-for-windows_11.html on Windows
-            left = subprocess.check_output(["py", "-%s" %pyver, "./xlsx2csv.py"] + arguments + ["test/%s.%s" %(case, ext)]).decode('utf-8').replace('\r','')
+            command = ["py", "-%s" %pyver] 
         else:
             print("os.name is unexpected: "+os.name)
             sys.exit(1)
+        left = subprocess.check_output(command + ["./xlsx2csv.py"] + arguments + ["test/%s.%s" %(case, ext)]).decode('utf-8').replace('\r','')
 
         f = open("test/%s.csv" %case, "r", encoding="utf-8", newline="")
         right = f.read().replace('\r','')
@@ -41,9 +42,28 @@ def compare(case, arguments=[]):
             failed = True
         else:
             print("OK: %s %s" %(case, pyver))
+
+        # test STDIN, only works for python3
+        if pyver == "2":
+            continue
+
+        xfile = open("test/%s.%s" %(case,ext), "rb")
+        stdin = xfile.read()
+        xfile.close()
+
+        pipe = subprocess.run(command + ["./xlsx2csv.py"] + arguments + ["-"], input = stdin, capture_output = True)
+        stdinleft = pipe.stdout.decode("utf-8").replace('\r','').replace('\r','')
+
+        if stdinleft != right:
+            print("FAILED (STDIN): %s %s" %(case, pyver))
+            failed = True
+        else:
+            print("OK (STDIN): %s %s" %(case, pyver))
+
     if failed:
         sys.exit(1)
 
+
 compare("datetime", ["--dateformat=%Y-%m-%d %H:%M:%S"])
 compare("empty_row")
 compare("junk-small")

xlsx2csv.py

@@ -1067,7 +1067,7 @@ def main():
 
     if "ArgumentParser" in globals():
         parser = ArgumentParser(description="xlsx to csv converter")
-        parser.add_argument('infile', metavar='xlsxfile', help="xlsx file path")
+        parser.add_argument('infile', metavar='xlsxfile', help="xlsx file path, use '-' to read from STDIN")
         parser.add_argument('outfile', metavar='outfile', nargs='?', help="output csv file path")
         parser.add_argument('-v', '--version', action='version', version=__version__)
         nargs_plus = "+"
@@ -1216,7 +1216,7 @@ def main():
     try:
         if os.path.isdir(options.infile):
             convert_recursive(options.infile, sheetid, outfile, kwargs)
-        elif not os.path.exists(options.infile):
+        elif not os.path.exists(options.infile) and options.infile != "-":
             raise InvalidXlsxFileException("Input file not found!")
         else:
             xlsx2csv = Xlsx2csv(options.infile, **kwargs)