syncable_cli/analyzer/vulnerability/checkers/

javascript.rs

use std::path::Path;
use std::process::Command;
use log::{info, warn};
use crate::analyzer::dependency_parser::{DependencyInfo, Language};
use crate::analyzer::runtime::{RuntimeDetector, PackageManager};
use crate::analyzer::tool_management::ToolDetector;
use crate::analyzer::vulnerability::{VulnerableDependency, VulnerabilityError, VulnerabilityInfo, VulnerabilitySeverity};
use super::MutableLanguageVulnerabilityChecker;
use serde_json::Value as JsonValue;

pub struct JavaScriptVulnerabilityChecker {
    tool_detector: ToolDetector,
}

impl JavaScriptVulnerabilityChecker {
    pub fn new() -> Self {
        Self {
            tool_detector: ToolDetector::new(),
        }
    }
    
    fn execute_audit_for_manager(
        &mut self,
        manager: &PackageManager,
        project_path: &Path,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        match manager {
            PackageManager::Bun => self.execute_bun_audit(project_path, dependencies),
            PackageManager::Npm => self.execute_npm_audit(project_path, dependencies),
            PackageManager::Yarn => self.execute_yarn_audit(project_path, dependencies),
            PackageManager::Pnpm => self.execute_pnpm_audit(project_path, dependencies),
            PackageManager::Unknown => Ok(None),
        }
    }
    
    fn execute_bun_audit(
        &mut self,
        project_path: &Path,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        // Check if bun is available
        let bun_status = self.tool_detector.detect_tool("bun");
        if !bun_status.available {
            warn!("bun not found, skipping bun audit");
            return Ok(None);
        }
        
        info!("Executing bun audit in {}", project_path.display());
        
        // Execute bun audit --json
        let output = Command::new("bun")
            .args(&["audit", "--json"])
            .current_dir(project_path)
            .output()
            .map_err(|e| VulnerabilityError::CommandError(
                format!("Failed to run bun audit: {}", e)
            ))?;
        
        // bun audit returns non-zero exit code when vulnerabilities found
        // This is expected behavior, not an error
        if !output.status.success() && !output.stdout.is_empty() {
            info!("bun audit completed with findings");
        }
        
        if output.stdout.is_empty() {
            return Ok(None);
        }
        
        // Parse bun audit output
        let audit_data: serde_json::Value = serde_json::from_slice(&output.stdout)
            .map_err(|e| VulnerabilityError::ParseError(
                format!("Failed to parse bun audit output: {}", e)
            ))?;
        
        self.parse_bun_audit_output(&audit_data, dependencies)
    }
    
    fn execute_npm_audit(
        &mut self,
        project_path: &Path,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        // Check if npm is available
        let npm_status = self.tool_detector.detect_tool("npm");
        if !npm_status.available {
            warn!("npm not found, skipping npm audit");
            return Ok(None);
        }
        
        info!("Executing npm audit in {}", project_path.display());
        
        // Execute npm audit --json
        let output = Command::new("npm")
            .args(&["audit", "--json"])
            .current_dir(project_path)
            .output()
            .map_err(|e| VulnerabilityError::CommandError(
                format!("Failed to run npm audit: {}", e)
            ))?;
        
        // npm audit returns 0 even when vulnerabilities are found
        // Non-zero exit code indicates an actual error
        if !output.status.success() && output.stdout.is_empty() {
            return Err(VulnerabilityError::CommandError(
                format!("npm audit failed with exit code {}: {}", 
                    output.status.code().unwrap_or(-1),
                    String::from_utf8_lossy(&output.stderr))
            ));
        }
        
        if output.stdout.is_empty() {
            return Ok(None);
        }
        
        // Parse npm audit output
        let audit_data: serde_json::Value = serde_json::from_slice(&output.stdout)
            .map_err(|e| VulnerabilityError::ParseError(
                format!("Failed to parse npm audit output: {}", e)
            ))?;
        
        self.parse_npm_audit_output(&audit_data, dependencies)
    }
    
    fn execute_yarn_audit(
        &mut self,
        project_path: &Path,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        // Check if yarn is available
        let yarn_status = self.tool_detector.detect_tool("yarn");
        if !yarn_status.available {
            warn!("yarn not found, skipping yarn audit");
            return Ok(None);
        }

        info!("Executing yarn audit in {}", project_path.display());

        // Strategy:
        // 1) Try Yarn Berry command: yarn npm audit --json (Yarn v2+)
        // 2) Fallback to classic: yarn audit --json (Yarn v1)
        // 3) Handle both single-JSON and line-delimited JSON formats
        let candidates: Vec<Vec<&str>> = vec![
            vec!["npm", "audit", "--json"],
            vec!["audit", "--json"],
        ];

        for args in candidates {
            let output = match Command::new("yarn").args(&args).current_dir(project_path).output() {
                Ok(o) => o,
                Err(e) => {
                    warn!("Failed to run 'yarn {}': {}", args.join(" "), e);
                    continue;
                }
            };

            // Non-zero with empty stdout is a hard failure; otherwise attempt to parse what we got
            if !output.status.success() && output.stdout.is_empty() {
                warn!(
                    "yarn {} failed (code {:?}): {}",
                    args.join(" "),
                    output.status.code(),
                    String::from_utf8_lossy(&output.stderr)
                );
                continue;
            }

            if output.stdout.is_empty() {
                // Nothing to parse
                continue;
            }

            // Try to parse as a single JSON blob first (be tolerant of banners/noise)
            if let Some(audit_data) = try_parse_json_tolerant(&output.stdout) {
                // If it looks like NPM's shape (common for `yarn npm audit`), reuse NPM parser
                if audit_data.get("vulnerabilities").is_some() {
                    if let Ok(res) = self.parse_npm_audit_output(&audit_data, dependencies) {
                        if res.is_some() { return Ok(res); }
                    }
                }

                // Otherwise try Yarn object shape
                if let Ok(res) = self.parse_yarn_audit_output(&audit_data, dependencies) {
                    if res.is_some() { return Ok(res); }
                }
            } else {
                // If not a single JSON, try line-delimited JSON format (Yarn v1 classic)
                if let Ok(res) = self.parse_yarn_streaming_audit_lines(&output.stdout, dependencies) {
                    if res.is_some() { return Ok(res); }
                }
            }
        }

        // If we got here, we couldn't parse Yarn output; don't fail the whole scan
        warn!("Unable to parse yarn audit output; skipping Yarn results");
        Ok(None)
    }
    
    fn execute_pnpm_audit(
        &mut self,
        project_path: &Path,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        // Check if pnpm is available
        let pnpm_status = self.tool_detector.detect_tool("pnpm");
        if !pnpm_status.available {
            warn!("pnpm not found, skipping pnpm audit");
            return Ok(None);
        }
        
        info!("Executing pnpm audit in {}", project_path.display());
        
        // Execute pnpm audit --json
        let output = Command::new("pnpm")
            .args(&["audit", "--json"])
            .current_dir(project_path)
            .output()
            .map_err(|e| VulnerabilityError::CommandError(
                format!("Failed to run pnpm audit: {}", e)
            ))?;
        
        // pnpm audit behavior: returns 0 even when vulnerabilities are found
        // Non-zero exit code indicates an actual error
        if !output.status.success() && output.stdout.is_empty() {
            return Err(VulnerabilityError::CommandError(
                format!("pnpm audit failed with exit code {}: {}", 
                    output.status.code().unwrap_or(-1),
                    String::from_utf8_lossy(&output.stderr))
            ));
        }
        
        if output.stdout.is_empty() {
            return Ok(None);
        }
        
        // Parse pnpm audit output
        let audit_data: serde_json::Value = serde_json::from_slice(&output.stdout)
            .map_err(|e| VulnerabilityError::ParseError(
                format!("Failed to parse pnpm audit output: {}", e)
            ))?;
        
        self.parse_pnpm_audit_output(&audit_data, dependencies)
    }
    
    fn parse_bun_audit_output(
        &self,
        audit_data: &serde_json::Value,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        let mut vulnerable_deps: Vec<VulnerableDependency> = Vec::new();
        
        // Bun audit JSON structure parsing
        // Bun returns a JSON object where keys are package names and values are arrays of vulnerabilities
        if let Some(obj) = audit_data.as_object() {
            for (package_name, vulnerabilities) in obj {
                if let Some(vuln_array) = vulnerabilities.as_array() {
                    // Include all vulnerable packages, not just direct dependencies
                    // Audit tools report on the entire dependency tree
                    let mut package_vulns = Vec::new();
                    
                    for vulnerability in vuln_array {
                        // Extract vulnerability information
                        let id = vulnerability.get("id").and_then(|i| i.as_u64())
                            .map(|id| id.to_string())
                            .unwrap_or("unknown".to_string());
                        let title = vulnerability.get("title").and_then(|t| t.as_str())
                            .unwrap_or("Unknown vulnerability").to_string();
                        let description = vulnerability.get("title").and_then(|t| t.as_str())
                            .unwrap_or("").to_string();
                        let severity = self.parse_severity(vulnerability.get("severity").and_then(|s| s.as_str()));
                        let affected_versions = vulnerability.get("vulnerable_versions").and_then(|v| v.as_str())
                            .unwrap_or("*").to_string();
                        let cwe = vulnerability.get("cwe").and_then(|c| c.as_array())
                            .and_then(|arr| arr.first())
                            .and_then(|v| v.as_str())
                            .map(|s| s.to_string());
                        let url = vulnerability.get("url").and_then(|u| u.as_str())
                            .map(|s| s.to_string());
                        
                        let vuln_info = VulnerabilityInfo {
                            id,
                            vuln_type: "security".to_string(),  // Security vulnerability
                            severity,
                            title,
                            description,
                            cve: cwe.clone(), // Using CWE as CVE for now
                            ghsa: url.clone().filter(|u| u.contains("GHSA")).map(|u| {
                                u.split('/').last().unwrap_or(&u).to_string()
                            }),
                            affected_versions,
                            patched_versions: None, // Bun doesn't provide this directly
                            published_date: None, // Bun audit may not provide this
                            references: url.map(|u| vec![u]).unwrap_or_default(),
                        };
                        
                        package_vulns.push(vuln_info);
                    }
                    
                    if !package_vulns.is_empty() {
                        // Try to find version from direct dependencies, otherwise use "transitive"
                        let version = dependencies.iter()
                            .find(|d| d.name == *package_name)
                            .map(|d| d.version.clone())
                            .unwrap_or_else(|| "transitive".to_string());
                        
                        vulnerable_deps.push(VulnerableDependency {
                            name: package_name.clone(),
                            version,
                            language: Language::JavaScript,
                            vulnerabilities: package_vulns,
                        });
                    }
                }
            }
        }
        
        if vulnerable_deps.is_empty() {
            Ok(None)
        } else {
            Ok(Some(vulnerable_deps))
        }
    }
    
    fn parse_npm_audit_output(
        &self,
        audit_data: &serde_json::Value,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        let mut vulnerable_deps: Vec<VulnerableDependency> = Vec::new();
        
        // NPM audit JSON structure parsing
        // NPM returns a JSON object with a "vulnerabilities" field containing package vulnerabilities
        if let Some(vulnerabilities) = audit_data.get("vulnerabilities").and_then(|v| v.as_object()) {
            for (package_name, vulnerability_info) in vulnerabilities {
                // Include all vulnerable packages, not just direct dependencies
                // Audit tools report on the entire dependency tree
                let mut package_vulns = Vec::new();
                
                // Get vulnerability details from the "via" array
                if let Some(via) = vulnerability_info.get("via").and_then(|v| v.as_array()) {
                    for advisory in via {
                        if let Some(advisory_obj) = advisory.as_object() {
                            // Skip if this is just a reference to another package
                            if advisory_obj.contains_key("source") && !advisory_obj.contains_key("title") {
                                continue;
                            }
                            
                            let id = advisory_obj.get("source")
                                .and_then(|s| s.as_u64())
                                .map(|id| id.to_string())
                                .or_else(|| advisory_obj.get("url")
                                    .and_then(|u| u.as_str())
                                    .and_then(|url| {
                                        if url.contains("GHSA") {
                                            url.split('/').last().map(|s| s.to_string())
                                        } else {
                                            None
                                        }
                                    }))
                                .unwrap_or("unknown".to_string());
                            
                            let title = advisory_obj.get("title").and_then(|t| t.as_str())
                                .unwrap_or("Unknown vulnerability").to_string();
                            let description = title.clone();
                            let severity = self.parse_severity(advisory_obj.get("severity").and_then(|s| s.as_str()));
                            
                            let range = advisory_obj.get("range").and_then(|r| r.as_str())
                                .unwrap_or("*").to_string();
                            
                            let cwe = advisory_obj.get("cwe").and_then(|c| c.as_array())
                                .and_then(|arr| arr.first())
                                .and_then(|v| v.as_str())
                                .map(|s| s.to_string());
                            
                            let url = advisory_obj.get("url").and_then(|u| u.as_str())
                                .map(|s| s.to_string());
                            
                            let vuln_info = VulnerabilityInfo {
                                id,
                                vuln_type: "security".to_string(),  // Security vulnerability
                                severity,
                                title,
                                description,
                                cve: cwe.clone(),
                                ghsa: url.clone().filter(|u| u.contains("GHSA")).map(|u| {
                                    u.split('/').last().unwrap_or(&u).to_string()
                                }),
                                affected_versions: range,
                                patched_versions: None, // NPM doesn't provide this directly in via
                                published_date: None,
                                references: url.map(|u| vec![u]).unwrap_or_default(),
                            };
                            
                            package_vulns.push(vuln_info);
                        }
                    }
                }
                
                if !package_vulns.is_empty() {
                    // Try to find version from direct dependencies, otherwise use "transitive"
                    let version = dependencies.iter()
                        .find(|d| d.name == *package_name)
                        .map(|d| d.version.clone())
                        .unwrap_or_else(|| "transitive".to_string());
                    
                    vulnerable_deps.push(VulnerableDependency {
                        name: package_name.clone(),
                        version,
                        language: Language::JavaScript,
                        vulnerabilities: package_vulns,
                    });
                }
            }
        }
        
        if vulnerable_deps.is_empty() {
            Ok(None)
        } else {
            Ok(Some(vulnerable_deps))
        }
    }
    
    fn parse_yarn_audit_output(
        &self,
        audit_data: &serde_json::Value,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        let mut vulnerable_deps: Vec<VulnerableDependency> = Vec::new();
        
        // Yarn audit JSON structure parsing
        // Shape 1: Single object with { data: { advisories: { id: {...} } } } (rare)
        if let Some(data) = audit_data.get("data").and_then(|d| d.as_object()) {
            if let Some(advisories) = data.get("advisories").and_then(|a| a.as_object()) {
                for (advisory_id, advisory) in advisories {
                    if let Some(advisory_obj) = advisory.as_object() {
                        let (vuln_info, pkg_name) = self.extract_yarn_advisory(advisory_id, advisory_obj);
                        // Include all vulnerable packages, not just direct dependencies
                        if let Some(existing) = vulnerable_deps.iter_mut().find(|v| v.name == pkg_name) {
                            existing.vulnerabilities.push(vuln_info);
                        } else {
                            // Try to find version from direct dependencies, otherwise use "transitive"
                            let version = dependencies.iter()
                                .find(|d| d.name == pkg_name)
                                .map(|d| d.version.clone())
                                .unwrap_or_else(|| "transitive".to_string());
                            
                            vulnerable_deps.push(VulnerableDependency {
                                name: pkg_name,
                                version,
                                language: Language::JavaScript,
                                vulnerabilities: vec![vuln_info],
                            });
                        }
                    }
                }
            }
        }
        
        if vulnerable_deps.is_empty() {
            Ok(None)
        } else {
            Ok(Some(vulnerable_deps))
        }
    }

    // Parse Yarn classic line-delimited JSON output
    fn parse_yarn_streaming_audit_lines(
        &self,
        stdout: &[u8],
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        let mut vulnerable_deps: Vec<VulnerableDependency> = Vec::new();
        let text = String::from_utf8_lossy(stdout);
        for line in text.lines() {
            let line = line.trim();
            if line.is_empty() { continue; }
            if let Ok(json) = serde_json::from_str::<serde_json::Value>(line) {
                if json.get("type").and_then(|t| t.as_str()) == Some("auditAdvisory") {
                    if let Some(advisory_obj) = json
                        .get("data")
                        .and_then(|d| d.get("advisory"))
                        .and_then(|a| a.as_object())
                    {
                        let package_name = advisory_obj
                            .get("module_name")
                            .and_then(|n| n.as_str())
                            .unwrap_or("")
                            .to_string();
                        let (vuln_info, pkg_name) = self.extract_yarn_advisory(
                            advisory_obj
                                .get("id")
                                .and_then(|v| v.as_i64())
                                .map(|v| v.to_string())
                                .unwrap_or_else(|| "unknown".to_string())
                                .as_str(),
                            advisory_obj,
                        );

                        // Include all vulnerable packages, not just direct dependencies
                        if let Some(existing) = vulnerable_deps.iter_mut().find(|v| v.name == pkg_name) {
                            existing.vulnerabilities.push(vuln_info);
                        } else {
                            // Try to find version from direct dependencies, otherwise use "transitive"
                            let version = dependencies.iter()
                                .find(|d| d.name == pkg_name)
                                .map(|d| d.version.clone())
                                .unwrap_or_else(|| "transitive".to_string());
                            
                            vulnerable_deps.push(VulnerableDependency {
                                name: pkg_name,
                                version,
                                language: Language::JavaScript,
                                vulnerabilities: vec![vuln_info],
                            });
                        }
                    }
                }
            }
        }

        if vulnerable_deps.is_empty() { Ok(None) } else { Ok(Some(vulnerable_deps)) }
    }

    fn extract_yarn_advisory<'a>(
        &self,
        advisory_id: impl Into<String>,
        advisory_obj: &serde_json::Map<String, serde_json::Value>,
    ) -> (VulnerabilityInfo, String) {
        let package_name = advisory_obj
            .get("module_name")
            .and_then(|n| n.as_str())
            .unwrap_or("")
            .to_string();
        let id = advisory_id.into();
        let title = advisory_obj.get("title").and_then(|t| t.as_str()).unwrap_or("Unknown vulnerability").to_string();
        let description = advisory_obj.get("overview").and_then(|o| o.as_str()).unwrap_or("").to_string();
        let severity = self.parse_severity(advisory_obj.get("severity").and_then(|s| s.as_str()));
        let vulnerable_versions = advisory_obj.get("vulnerable_versions").and_then(|v| v.as_str()).unwrap_or("*").to_string();
        let cve = advisory_obj
            .get("cves")
            .and_then(|c| c.as_array())
            .and_then(|arr| arr.first())
            .and_then(|v| v.as_str())
            .map(|s| s.to_string());
        let url = advisory_obj.get("url").and_then(|u| u.as_str()).map(|s| s.to_string());

        let vuln_info = VulnerabilityInfo {
            id,
            vuln_type: "security".to_string(),
            severity,
            title,
            description,
            cve,
            ghsa: url.clone().filter(|u| u.contains("GHSA")).map(|u| u.split('/').last().unwrap_or(&u).to_string()),
            affected_versions: vulnerable_versions,
            patched_versions: advisory_obj.get("patched_versions").and_then(|p| p.as_str()).map(|s| s.to_string()),
            published_date: None,
            references: url.map(|u| vec![u]).unwrap_or_default(),
        };

        (vuln_info, package_name)
    }
    
    fn parse_pnpm_audit_output(
        &self,
        audit_data: &serde_json::Value,
        dependencies: &[DependencyInfo],
    ) -> Result<Option<Vec<VulnerableDependency>>, VulnerabilityError> {
        // PNPM audit output can resemble NPM or provide an advisories map similar to Yarn classic
        if audit_data.get("vulnerabilities").is_some() {
            return self.parse_npm_audit_output(audit_data, dependencies);
        }

        if let Some(advisories) = audit_data.get("advisories").cloned() {
            // Wrap into Yarn-like shape and reuse Yarn parser
            let yarn_like = serde_json::json!({
                "data": { "advisories": advisories }
            });
            return self.parse_yarn_audit_output(&yarn_like, dependencies);
        }

        // Some pnpm versions produce per-advisory arrays; attempt best-effort mapping if present
        if let Some(findings) = audit_data.get("audit").or_else(|| audit_data.get("metadata")).or_else(|| audit_data.get("data")) {
            // Try npm parser as a reasonable default
            if let Ok(res) = self.parse_npm_audit_output(audit_data, dependencies) {
                if res.is_some() { return Ok(res); }
            }
        }

        Ok(None)
    }
    
    fn parse_severity(&self, severity: Option<&str>) -> VulnerabilitySeverity {
        match severity.map(|s| s.to_lowercase()).as_deref() {
            Some("critical") => VulnerabilitySeverity::Critical,
            Some("high") => VulnerabilitySeverity::High,
            Some("moderate") => VulnerabilitySeverity::Medium,
            Some("medium") => VulnerabilitySeverity::Medium,
            Some("low") => VulnerabilitySeverity::Low,
            _ => VulnerabilitySeverity::Medium, // Default to medium if not specified
        }
    }
}

impl MutableLanguageVulnerabilityChecker for JavaScriptVulnerabilityChecker {
    fn check_vulnerabilities(
        &mut self,
        dependencies: &[DependencyInfo],
        project_path: &Path,
    ) -> Result<Vec<VulnerableDependency>, VulnerabilityError> {
        info!("Checking JavaScript/TypeScript dependencies");
        
        let runtime_detector = RuntimeDetector::new(project_path.to_path_buf());
        let detection_result = runtime_detector.detect_js_runtime_and_package_manager();

        info!("Runtime detection: {}", runtime_detector.get_detection_summary());

        // Build execution order: primary detected manager first, then any lockfile-based managers
        let mut managers = Vec::new();
        if detection_result.package_manager != crate::analyzer::runtime::PackageManager::Unknown {
            managers.push(detection_result.package_manager.clone());
        }
        for m in runtime_detector.detect_all_package_managers() {
            if !managers.contains(&m) {
                managers.push(m);
            }
        }

        // Always consider running Bun audit for JS projects if available,
        // as Bun often surfaces advisories even when other managers don't.
        if !managers.contains(&crate::analyzer::runtime::PackageManager::Bun)
            && runtime_detector.is_js_project()
        {
            managers.push(crate::analyzer::runtime::PackageManager::Bun);
        }

        // If still empty but it's a JS project, default to npm as a last resort
        if managers.is_empty() && runtime_detector.is_js_project() {
            managers.push(crate::analyzer::runtime::PackageManager::Npm);
        }

        // Execute audit commands for each selected manager
        let mut all_vulnerabilities = Vec::new();

        for manager in managers {
            if let Some(vulns) = self.execute_audit_for_manager(&manager, project_path, dependencies)? {
                all_vulnerabilities.extend(vulns);
            }
        }
        
        // Deduplicate vulnerabilities by package name and vulnerability ID
        let mut deduplicated: Vec<VulnerableDependency> = Vec::new();
        for vuln_dep in all_vulnerabilities {
            if let Some(existing) = deduplicated.iter_mut().find(|d| d.name == vuln_dep.name) {
                // Merge vulnerabilities, avoiding duplicates by ID
                for new_vuln in vuln_dep.vulnerabilities {
                    if !existing.vulnerabilities.iter().any(|v| v.id == new_vuln.id) {
                        existing.vulnerabilities.push(new_vuln);
                    }
                }
            } else {
                deduplicated.push(vuln_dep);
            }
        }
        
        Ok(deduplicated)
    }
}

// Best-effort tolerant JSON extractor: handles banners/noise by
// 1) parsing whole buffer, 2) slicing between first '{' and last '}',
// 3) scanning lines for a valid JSON object.
fn try_parse_json_tolerant(buf: &[u8]) -> Option<JsonValue> {
    if let Ok(val) = serde_json::from_slice::<JsonValue>(buf) {
        return Some(val);
    }
    let text = String::from_utf8_lossy(buf);
    if let (Some(start), Some(end)) = (text.find('{'), text.rfind('}')) {
        if start < end {
            if let Ok(val) = serde_json::from_str::<JsonValue>(&text[start..=end]) {
                return Some(val);
            }
        }
    }
    for line in text.lines() {
        let line = line.trim();
        if !line.starts_with('{') || !line.ends_with('}') { continue; }
        if let Ok(val) = serde_json::from_str::<JsonValue>(line) {
            return Some(val);
        }
    }
    None
}