DiceDB#1018 Migration: Append, GetRange (DiceDB#1095)

docs/src/content/docs/commands/APPEND.md

@@ -0,0 +1,73 @@
+---
+title: APPEND
+description: The `APPEND` command in DiceDB is used to either set the value of a key or append a value to an existing key. This command allows for both creating and updating key-value pairs.
+---
+The `APPEND` command in DiceDB is used to either set the value of a key or append a value to an existing key. This command allows for both creating and updating key-value pairs.
+
+## Syntax
+
+```bash
+APPEND key value
+```
+
+## Parameters
+| Parameter | Description                                                               | Type    | Required |
+|-----------|---------------------------------------------------------------------------|---------|----------|
+| `key`     | The name of the key to be set.                                            | String  | Yes      |
+| `value`   | The value to be set for the key.                                          | String  | Yes      |
+
+## Return values
+
+| Condition                                      | Return Value                                      |
+|------------------------------------------------|---------------------------------------------------|
+| if key is set successfully                     | length of the string.                             |
+
+## Behaviour
+- If the specified key does not exist, the `APPEND` command will create a new key-value pair. 
+- If the specified key already exists, the `APPEND` command will append the value to the existing value of the key.
+
+
+## Errors
+1. `Wrong type of value or key`:
+
+   - Error Message: `(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value`
+   - Occurs when attempting to use the command on a key that contains a non-string value.
+
+2. `Invalid syntax or conflicting options`:
+
+   - Error Message: `(error) ERROR wrong number of arguments for 'append' command`
+   - If the number of arguments are not exactly equal to 2.
+
+## Example Usage
+
+### Basic Usage
+
+Setting a key `foo` with the value `bar` using `APPEND`
+
+```bash
+127.0.0.1:7379> APPEND foo bar
+(integer) 3
+```
+
+Appending to key `foo` that contains `bar` with `baz` 
+
+```bash
+127.0.0.1:7379> SET foo bar
+127.0.0.1:7379> APPEND foo baz
+(integer) 6
+```
+
+### Invalid usage
+
+Trying to use `APPEND` without giving the value
+
+```bash
+127.0.0.1:7379> APPEND foo
+(error) ERROR wrong number of arguments for 'append' command
+```
+Trying to use `APPEND` on a invalid data type.
+```bash
+127.0.0.1:7379> LPUSH foo bar
+127.0.0.1:7379> APPEND foo baz
+(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value
+```

docs/src/content/docs/commands/GETRANGE.MD

@@ -0,0 +1,107 @@
+---
+title: GETRANGE
+description: The `GETRANGE` command in DiceDB is used to get a substring of a string, provided the start and end indices
+---
+The `GETRANGE` command in DiceDB is used to get a substring of a string, provided the start and end indices.
+
+## Syntax
+
+```bash
+GETRANGE key start end
+```
+
+## Parameters
+| Parameter | Description                                                               | Type    | Required |
+|-----------|---------------------------------------------------------------------------|---------|----------|
+| `key`     | The name of the key containing the string.                                           | String  | Yes      |
+| `start`   | The starting index of the required substring.                              | Integer | Yes      |
+| `end`     | The ending index of the required substring.                               | Integer | Yes      |
+## Return values
+
+| Condition                                      | Return Value                                      |
+|------------------------------------------------|---------------------------------------------------|
+| if key contains a valid string                 | a substring based on the start and end indices    |
+| if `start` is greater than `end`               | an empty string is returned                       |
+| if the `end` exceeds the length of the string present at `key` | the entire string is returned     |
+| if the `start` is greater than the length of the string | an empty string is returned.             |
+
+## Behaviour
+- If the specified key does not exist, the `GETRANGE` command returns an empty string. 
+- If `start` is greater than `end`, the `GETRANGE` command returns an empty string.
+- If `start` is not within the length of the string, the `GETRANGE` command returns an empty string.
+- `start` and `end` can be negative which removed `end + 1` characters from the other side of the string.
+- Both `start` and `end` can be negative, which removes characters from the string, starting from the `end + 1` position on the right.
+
+## Errors
+1. `Wrong type of value or key`:
+
+   - Error Message: `(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value`
+   - Occurs when attempting to use the command on a key that contains a non-string value.
+
+2. `Invalid syntax or conflicting options`:
+
+   - Error Message: `(error) ERROR wrong number of arguments for 'GETRANGE' command`
+   - If the number of arguments are not exactly equal to 4.
+
+3. `Invalid input type for start and end`
+
+   - Error Message: `(error) ERROR value is not an integer or out of range`
+   - If `start` and `end` are not integers.
+
+## Example Usage
+
+### Basic Usage
+
+Assume we have a string stored in `foo`
+
+```bash
+127.0.0.1:7379> SET foo apple
+OK
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo 1 3
+"ppl"
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo 0 -1
+"apple"
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo 0 -10
+""
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo 0 -2
+"appl"
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo 0 1001
+"apple"
+```
+
+### Invalid usage
+
+Trying to use `GETRANGE` without giving the value
+
+```bash
+127.0.0.1:7379> GETRANGE foo
+(error) ERROR wrong number of arguments for 'getrange' command
+```
+
+Trying to use `GETRANGE` on an invalid data type.
+
+```bash
+127.0.0.1:7379> LPUSH foo apple
+127.0.0.1:7379> GETRANGE foo 0 5
+(error) ERROR WRONGTYPE Operation against a key holding the wrong kind of value
+```
+
+```bash
+127.0.0.1:7379> GETRANGE foo s e
+(error) ERROR value is not an integer or out of range
+```

integration_tests/commands/http/append_test.go

@@ -0,0 +1,104 @@
+package http
+
+import (
+	"testing"
+
+	testifyAssert "github.com/stretchr/testify/assert"
+)
+
+func TestAPPEND(t *testing.T) {
+	exec := NewHTTPCommandExecutor()
+	testCases := []struct {
+		name     string
+		commands []HTTPCommand
+		expected []interface{}
+		cleanup  []HTTPCommand
+	}{
+		{
+			name: "APPEND and GET a new Val",
+			commands: []HTTPCommand{
+				{Command: "APPEND", Body: map[string]interface{}{"key": "k", "value": "newVal"}},
+				{Command: "GET", Body: map[string]interface{}{"key": "k"}},
+			},
+			expected: []interface{}{float64(6), "newVal"},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "k"}},
+			},
+		},
+		{
+			name: "APPEND to an exisiting key and GET",
+			commands: []HTTPCommand{
+				{Command: "SET", Body: map[string]interface{}{"key": "k", "value": "Bhima"}},
+				{Command: "APPEND", Body: map[string]interface{}{"key": "k", "value": "Shankar"}},
+				{Command: "GET", Body: map[string]interface{}{"key": "k"}},
+			},
+			expected: []interface{}{"OK", float64(12), "BhimaShankar"},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "k"}},
+			},
+		},
+		{
+			name: "APPEND without input value",
+			commands: []HTTPCommand{
+				{Command: "APPEND", Body: map[string]interface{}{"key": "k"}},
+			},
+			expected: []interface{}{"ERR wrong number of arguments for 'append' command"},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "k"}},
+			},
+		},
+		{
+			name: "APPEND empty string to an exsisting key with empty string",
+			commands: []HTTPCommand{
+				{Command: "SET", Body: map[string]interface{}{"key": "k", "value": ""}},
+				{Command: "APPEND", Body: map[string]interface{}{"key": "k", "value": ""}},
+			},
+			expected: []interface{}{"OK", float64(0)},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "k"}},
+			},
+		},
+		{
+			name: "APPEND to key created using LPUSH",
+			commands: []HTTPCommand{
+				{Command: "LPUSH", Body: map[string]interface{}{"key": "m", "value": "bhima"}},
+				{Command: "APPEND", Body: map[string]interface{}{"key": "m", "value": "shankar"}},
+			},
+			expected: []interface{}{float64(1), "WRONGTYPE Operation against a key holding the wrong kind of value"},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "m"}},
+			},
+		},
+		{
+			name: "APPEND value with leading zeros",
+			commands: []HTTPCommand{
+				{Command: "APPEND", Body: map[string]interface{}{"key": "z", "value": "0043"}},
+			},
+			expected: []interface{}{float64(4)},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "z"}},
+			},
+		},
+		{
+			name: "APPEND to key created using SADD",
+			commands: []HTTPCommand{
+				{Command: "SADD", Body: map[string]interface{}{"key": "key", "value": "apple"}},
+				{Command: "APPEND", Body: map[string]interface{}{"key": "key", "value": "banana"}},
+			},
+			expected: []interface{}{float64(1), "WRONGTYPE Operation against a key holding the wrong kind of value"},
+			cleanup: []HTTPCommand{
+				{Command: "del", Body: map[string]interface{}{"key": "key"}},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+
+			for i, cmd := range tc.commands {
+				result, _ := exec.FireCommand(cmd)
+				testifyAssert.Equal(t, tc.expected[i], result)
+			}
+			exec.FireCommand(tc.cleanup[0])
+		})
+	}
+}