Create file_utils.py

other/file_utils.py

@@ -0,0 +1,169 @@
+import json
+import sys
+
+# A utility file for all basic plain text and JSON file IO
+
+
+def touch_file(file_name: str) -> None:
+    """
+    Touch file:
+    Checks if the file file_name exist else tries to create it.
+    Similar to touch command on linux.
+    """
+    try:
+        with open(file_name):
+            pass
+    except FileNotFoundError:
+        try:
+            with open(file_name, "w"):
+                pass
+        except IOError as ioe:
+            sys.exit("{}: Unable to create {}".format(ioe, file_name))
+    except IOError as ioe:
+        sys.exit("{}: Unable to read file {}".format(ioe, file_name))
+
+
+def clear_file(file_name: str) -> None:
+    """
+    Clear file:
+    A utility function to clear the contents of the file file_name.
+    """
+    try:
+        with open(file_name, "w"):
+            pass
+    except IOError as ioe:
+        sys.exit("{}: Unable to create file {}".format(ioe, file_name))
+
+
+def dump_json_to_file(data: object, file_name: str) -> None:
+    """
+    Dump JSON to file:
+    - Creates the file file_name if it doesn't exist already.
+    - Clears the content of the file file_name.
+    - Converts the data object into JSON format and dumps it into the file file_name.
+    """
+    touch_file(file_name)
+    with open(file_name, "w") as write_file:
+        write_file.write(json.dumps(data, indent=4) + "\n")
+
+
+def load_json_from_file(file_name: str) -> str:
+    """
+    Load JSON from file:
+    - Creates the file file_name if it doesn't exist already.
+    - Read the content of the file file_name.
+    - Converts the data inside the file_name into JSON format and returns it.
+    - Returns str representation of an empty dict if the file is empty.
+    """
+    touch_file(file_name)
+    with open(file_name) as readfile:
+        return readfile.read() or str({})
+
+
+def read_lines_strip_return(
+    file_name: str, split: str = None, index: int = None
+) -> list:
+    """
+    Read Lines from file:
+    - Read the content of the file file_name using readlines.
+    - If the parameter split is specified then each line is split using it.
+    - If the index is specified, index from the above split line is returned.
+    - Returns list of lines from file_name matching the split and index conditions.
+    """
+    try:
+        with open(file_name) as readfile:
+            lines = readfile.readlines()
+            res = list()
+            for line in lines:
+                line = line.strip()
+                if line != "":
+                    if split is not None:
+                        line = line.split(split)
+                        if index is None:
+                            res.append(line)
+                        else:
+                            res.append(line[index])
+                    else:
+                        res.append(line)
+        return res
+    except FileNotFoundError as fn_fe:
+        sys.exit("{}: {}".format(fn_fe, file_name))
+    except IOError as ioe:
+        sys.exit("{}: Unable to read file {}".format(ioe, file_name))
+
+
+def read_file(file_name: str) -> str:
+    """
+    Read file:
+    - Read the content of the file file_name using read and returns it.
+    """
+    try:
+        with open(file_name) as readfile:
+            return readfile.read().strip()
+    except FileNotFoundError as fn_fe:
+        sys.exit("{}: {}".format(fn_fe, file_name))
+    except IOError as ioe:
+        sys.exit("{}: Unable to read file {}".format(ioe, file_name))
+
+
+def append_line_to_file(file_name: str, line: str) -> None:
+    """
+    Append Line to file:
+    - Checks if the file exists and creates if not.
+    - Opens the file in append mode and appends the line at the ending of file_name.
+    """
+    touch_file(file_name)
+    with open(file_name, "a") as append_file:
+        append_file.write(line + "\n")
+
+
+def append_line_to_file_if_doesnt_exist(file_name: str, line: str) -> None:
+    """
+    Append Line to file only if not exists:
+    - Checks if the file exists and creates if not.
+    - Checks if the line already exists in the file file_name.
+    - Only appends the line if nor already present in file_name.
+    """
+    touch_file(file_name)
+    lines = read_lines_strip_return(file_name)
+    if line not in lines:
+        with open(file_name, "a") as append_file:
+            append_file.write(line + "\n")
+
+
+def check_file_exists(file_name: str) -> bool:
+    """
+    Check if file exists:
+    - Checks whether the file file_name exists or not.
+    """
+    try:
+        with open(file_name):
+            pass
+        return True
+    except FileNotFoundError:
+        return False
+    except IOError:
+        return False
+
+
+def convert_int_to_dotted_str(number: int) -> str:
+    """
+    Convert int into dotted str:
+    - This function takes an integer and converts it into a dotted str.
+    - Useful in converting a number into version.
+    - Eg: 123 -> "1.2.3"
+    """
+    res = list()
+    for digit in str(number):
+        res.append(digit)
+    return ".".join(res)
+
+
+def convert_dotted_str_to_int(dotted_str: str) -> int:
+    """
+    Convert dotted str into int:
+    - This function takes a dotted str and converts into an int.
+    - Useful in converting version into a number.
+    - Eg: "1.2.3" -> 123
+    """
+    return int("".join(dotted_str.split(".")))