Genkit MCP

// Copyright 2024 Google LLC // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package base import ( "encoding/json" "strings" ) // ExtractJSON extracts JSON from string with lenient parsing rules. // It handles both complete and partial JSON structures. func ExtractJSON(text string) (any, error) { var openingChar, closingChar rune var startPos int = -1 nestingCount := 0 inString := false escapeNext := false for i, char := range text { // Replace non-breaking space with regular space if char == '\u00A0' { char = ' ' } if escapeNext { escapeNext = false continue } if char == '\\' { escapeNext = true continue } if char == '"' { inString = !inString continue } if inString { continue } if openingChar == 0 && (char == '{' || char == '[') { // Look for opening character openingChar = char if char == '{' { closingChar = '}' } else { closingChar = ']' } startPos = i nestingCount++ } else if char == openingChar { // Increment nesting for matching opening character nestingCount++ } else if char == closingChar { // Decrement nesting for matching closing character nestingCount-- if nestingCount == 0 { // Reached end of target element jsonStr := text[startPos : i+1] var result any err := json.Unmarshal([]byte(jsonStr), &result) if err != nil { return nil, err } return result, nil } } } if startPos != -1 && nestingCount > 0 { // If an incomplete JSON structure is detected, try to parse it partially jsonStr := text[startPos:] result, err := ParsePartialJSON(jsonStr) if err != nil { return nil, err } return result, nil } return nil, nil } // ParsePartialJSON attempts to parse incomplete JSON by completing it. func ParsePartialJSON(jsonStr string) (any, error) { // Try to parse as-is first var result any err := json.Unmarshal([]byte(jsonStr), &result) if err == nil { return result, nil } // If it fails, try to complete the JSON structure completed := CompleteJSON(jsonStr) err = json.Unmarshal([]byte(completed), &result) return result, err } // CompleteJSON attempts to complete an incomplete JSON string. func CompleteJSON(jsonStr string) string { jsonStr = strings.TrimSpace(jsonStr) if jsonStr == "" { return "{}" } // Count unclosed structures var openBraces, openBrackets int inString := false escapeNext := false for _, char := range jsonStr { if escapeNext { escapeNext = false continue } if char == '\\' { escapeNext = true continue } if char == '"' { inString = !inString continue } if inString { continue } switch char { case '{': openBraces++ case '}': openBraces-- case '[': openBrackets++ case ']': openBrackets-- } } // Close any unclosed string if inString { jsonStr += "\"" } // Remove trailing comma if present (before closing) jsonStr = strings.TrimRight(jsonStr, " \t\n\r") jsonStr = strings.TrimSuffix(jsonStr, ",") // Close open structures for i := 0; i < openBrackets; i++ { jsonStr += "]" } for i := 0; i < openBraces; i++ { jsonStr += "}" } return jsonStr } // ExtractItemsResult contains the result of extracting items from an array. type ExtractItemsResult struct { Items []any Cursor int } // ExtractItems extracts complete objects from the first array found in the text. // Processes text from the cursor position and returns both complete items // and the new cursor position. func ExtractItems(text string, cursor int) ExtractItemsResult { items := []any{} currentCursor := cursor // Find the first array start if we haven't already processed any text if cursor == 0 { arrayStart := strings.Index(text, "[") if arrayStart == -1 { return ExtractItemsResult{Items: items, Cursor: len(text)} } currentCursor = arrayStart + 1 } objectStart := -1 braceCount := 0 inString := false escapeNext := false // Process the text from the cursor position for i := currentCursor; i < len(text); i++ { char := rune(text[i]) if escapeNext { escapeNext = false continue } if char == '\\' { escapeNext = true continue } if char == '"' { inString = !inString continue } if inString { continue } if char == '{' { if braceCount == 0 { objectStart = i } braceCount++ } else if char == '}' { braceCount-- if braceCount == 0 && objectStart != -1 { var obj any err := json.Unmarshal([]byte(text[objectStart:i+1]), &obj) if err == nil { items = append(items, obj) currentCursor = i + 1 objectStart = -1 } } } else if char == ']' && braceCount == 0 { // End of array break } } return ExtractItemsResult{ Items: items, Cursor: currentCursor, } }