Переименования

server/core/FileDetector/index.js

@@ -0,0 +1,274 @@
+const fs = require('fs');
+const signatures = require('./signatures.json');
+
+class FileDetector {
+    detectFile(filename) {
+        return new Promise((resolve, reject) => {
+            this.fromFile(filename, 2000, (err, result) => {
+                if (err) reject(err);
+                resolve(result);
+            });
+        });
+    }
+
+    //все, что ниже, взято здесь: https://github.com/dimapaloskin/detect-file-type
+    fromFile(filePath, bufferLength, callback) {
+        if (typeof bufferLength === 'function') {
+            callback = bufferLength;
+            bufferLength = undefined;
+        }
+
+        this.getFileSize(filePath, (err, fileSize) => {
+            if (err) {
+                return callback(err);
+            }
+
+            fs.open(filePath, 'r', (err, fd) => {
+                if (err) {
+                    return callback(err);
+                }
+
+                let bufferSize = bufferLength;
+                if (!bufferSize) {
+                    bufferSize = 500;
+                }
+
+                if (fileSize < bufferSize) {
+                    bufferSize = fileSize;
+                }
+
+                const buffer = Buffer.alloc(bufferSize);
+
+                fs.read(fd, buffer, 0, bufferSize, 0, (err) => {
+                    fs.close(fd);
+
+                    if (err) {
+                      return callback(err);
+                    }
+
+                    this.fromBuffer(buffer, callback);
+                });
+            });
+        });
+    }
+
+    fromBuffer(buffer, callback) {
+        let result = null;
+
+        const invalidSignaturesList = this.validateSigantures();
+        if (invalidSignaturesList.length) {
+            return callback(invalidSignaturesList);
+        }
+
+        signatures.every((signature) => {
+            if (this.detect(buffer, signature.rules)) {
+                result = {
+                    ext: signature.ext,
+                    mime: signature.mime
+                };
+
+                if (signature.iana)
+                    result.iana = signature.iana;
+
+                return false;
+            }
+            return true;
+        });
+
+        callback(null, result);
+    }
+
+    detect(buffer, receivedRules, type) {
+        if (!type) {
+            type = 'and';
+        }
+
+        const rules = [...receivedRules];
+
+        let isDetected = true;
+        rules.every((rule) => {
+            if (rule.type === 'equal') {
+                const slicedHex = buffer.slice(rule.start || 0, rule.end || buffer.length).toString('hex');
+                isDetected = (slicedHex === rule.bytes);
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            if (rule.type === 'notEqual') {
+                const slicedHex = buffer.slice(rule.start || 0, rule.end || buffer.length).toString('hex');
+                isDetected = !(slicedHex === rule.bytes);
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            if (rule.type === 'contains') {
+                const slicedHex = buffer.slice(rule.start || 0, rule.end || buffer.length).toString('hex');
+                if (typeof rule.bytes === 'string') {
+                    rule.bytes = [rule.bytes];
+                }
+
+                rule.bytes.every((bytes) => {
+                    isDetected = (slicedHex.indexOf(bytes) !== -1);
+                    return isDetected;
+                });
+
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            if (rule.type === 'notContains') {
+                const slicedHex = buffer.slice(rule.start || 0, rule.end || buffer.length).toString('hex');
+                if (typeof rule.bytes === 'string') {
+                    rule.bytes = [rule.bytes];
+                }
+
+                rule.bytes.every((bytes) => {
+                    isDetected = (slicedHex.indexOf(bytes) === -1);
+                    return isDetected;
+                });
+
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            if (rule.type === 'or') {
+                isDetected = this.detect(buffer, rule.rules, 'or');
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            if (rule.type === 'and') {
+                isDetected = this.detect(buffer, rule.rules, 'and');
+                return this.isReturnFalse(isDetected, type);
+            }
+
+            return true;
+        });
+
+        return isDetected;
+    }
+
+    isReturnFalse(isDetected, type) {
+        if (!isDetected && type === 'and') {
+            return false;
+        }
+
+        if (isDetected && type === 'or') {
+            return false;
+        }
+
+        return true;
+    }
+
+    validateRuleType(rule) {
+        const types = ['or', 'and', 'contains', 'notContains', 'equal', 'notEqual'];
+        return  (types.indexOf(rule.type) !== -1);
+    }
+
+    validateSigantures() {
+        let invalidSignatures = signatures.map((signature) => {
+            return this.validateSignature(signature);
+        });
+
+        invalidSignatures = this.cleanArray(invalidSignatures);
+
+        if (invalidSignatures.length) {
+            return invalidSignatures;
+        }
+
+        return true;
+    }
+
+    validateSignature(signature) {
+        if (!('type' in signature)) {
+            return {
+                message: 'signature does not contain "type" field',
+                signature
+            };
+        }
+
+        if (!('ext' in signature)) {
+            return {
+                message: 'signature does not contain "ext" field',
+                signature
+            };
+        }
+
+        if (!('mime' in signature)) {
+            return {
+                message: 'signature does not contain "mime" field',
+                signature
+            };
+        }
+
+        if (!('rules' in signature)) {
+            return {
+                message: 'signature does not contain "rules" field',
+                signature
+            };
+        }
+
+        const invalidRules = this.validateRules(signature.rules);
+
+        if (invalidRules && invalidRules.length) {
+            return {
+                message: 'signature has invalid rule',
+                signature,
+                rules: invalidRules
+            }
+        }
+    }
+
+    validateRules(rules) {
+        let invalidRules = rules.map((rule) => {
+            let isRuleTypeValid = this.validateRuleType(rule);
+
+            if (!isRuleTypeValid) {
+                return {
+                    message: 'rule type does not supported',
+                    rule
+                };
+            }
+
+            if ((rule.type === 'or' || rule.type === 'and') && !('rules' in rule)) {
+                return {
+                    message: 'rule should contains "rules" field',
+                    rule
+                };
+            }
+
+            if (rule.type === 'or' || rule.type === 'and') {
+                return this.validateRules(rule.rules);
+            }
+
+            return false;
+        });
+
+        invalidRules = this.cleanArray(invalidRules);
+
+        if (invalidRules.length) {
+            return invalidRules;
+        }
+    }
+
+    cleanArray(actual) {
+        let newArray = new Array();
+        for (let i = 0; i < actual.length; i++) {
+            if (actual[i]) {
+                newArray.push(actual[i]);
+            }
+        }
+        return newArray;
+    }
+
+    addSignature(signature) {
+        signatures.push(signature);
+    }
+
+    getFileSize(filePath, callback) {
+        fs.stat(filePath, (err, stat) => {
+            if (err) {
+                return callback(err);
+            }
+
+            return callback(null, stat.size);
+        });
+    }
+}
+
+module.exports = FileDetector;