百度 AI 提供了一个出租车发票扫描接口：
https://ai.baidu.com/ai-doc/OCR/Zk3h7xxnn
支持识别全国各大城市出租车票的 16 个关键字段，包括发票号码、代码、车号、日期、总金额、燃油附加费、叫车服务费、省、市、单价、里程、上车时间、下车时间等。
我们首先在 postman 里调用该接口。
url：https://aip.baidubce.com/rest/2.0/ocr/v1/taxi_receipt?access_token=[这里传入 Access Token]
按照接口文档的说明，content-type 设置为 application/x-www-form-urlencoded：
在 body 里，类型选择为 x-www-form-urlencoded:
指定参数的 key 为 image，value 为发票图片二进制数据对应的 base 64 编码的 url encode 值。
下图是一个例子。点击 Send 按钮，会收到下图所示的响应数据，该发票里的关键信息被 API 成功解析。
这里我们需要注意一点，在 postman 里，我们指定参数 image 的值，是没有经过 url encode 的图片 base64 encode 的值，即下图图例 A。
而 postman 在发送该 HTTP 请求时，会自动把该base 64 的值做一次 url encode 处理，比如 base64 里的符号 “/”, 被处理成了 %2F. 见上图 B 的图例。
也就是说，我们在编写 ABAP 代码时，需要手动调用 cl_http_utility=>escape_url 执行这个 encode 动作。
下面是 ABAP 代码实现，逻辑不难。
report z. DATA: http_client TYPE REF TO if_http_client. DATA: ls_token TYPE string. DATA: lv_token TYPE string. DATA: url type string. url = 'https://aip.baidubce.com/rest/2.0/ocr/v1/taxi_receipt'. ls_token = '这里需要填写你实际获取的 Access Token'. CONCATENATE url '?access_token=' ls_token INTO lv_token. CALL METHOD cl_http_client=>create_by_url EXPORTING url = lv_token IMPORTING client = http_client. http_client->propertytype_logon_popup = http_client->co_enabled . http_client->propertytype_redirect = http_client->co_disabled . CALL METHOD http_client->request->set_header_field EXPORTING name = '~request_method' value = 'POST'. " CALL METHOD http_client->request->set_header_field EXPORTING name = '~request_protocol' value = 'HTTPS/1.1'. CALL METHOD http_client->request->set_header_field EXPORTING name = 'Content-Type' value = 'application/x-www-form-urlencoded; charset=utf-8'. *----------上传图片并转换成base64格式 start------------ types: begin of ty_pic, pic_data(1024) type x, end of ty_pic. data: path_string type string. *parameters: p_file like rlgrap-filename obligatory. data: lv_content type xstring. data: encode_str type string. data: len type i. data: pic_tab type table of ty_pic."二进制内表 * path_string = p_file. call function 'GUI_UPLOAD' exporting "filename = path_string filename = 'C:\Users\I042416\Documents\1.jpg' filetype = 'BIN' importing filelength = len tables data_tab = pic_tab[]. call function 'SCMS_BINARY_TO_XSTRING' exporting input_length = len importing buffer = lv_content tables binary_tab = pic_tab[] exceptions failed = 1 others = 2. " xstring转base64 CALL FUNCTION 'SCMS_BASE64_ENCODE_STR' EXPORTING input = lv_content IMPORTING output = encode_str. *----------上传图片并转换成base64格式 end-------------- "set body body内传base64格式图片 data: gv_json_send TYPE string. data: lv_len TYPE i. encode_str = cl_http_utility=>escape_url( encode_str ). CONCATENATE 'image=' encode_str INTO gv_json_send. lv_len = strlen( gv_json_send ). CALL METHOD HTTP_CLIENT->REQUEST->SET_CDATA EXPORTING DATA = gv_json_send OFFSET = 0 LENGTH = lv_len. CALL METHOD http_client->send EXCEPTIONS http_communication_failure = 1 http_invalid_state = 2. CALL METHOD http_client->receive EXCEPTIONS http_communication_failure = 1 http_invalid_state = 2 http_processing_failed = 3. IF sy-subrc <> 0. DATA:l_sysubrc TYPE sysubrc, l_error_text TYPE string. l_sysubrc = sy-subrc. CALL METHOD http_client->get_last_error IMPORTING code = l_sysubrc message = l_error_text. ENDIF. "Read HTTP RETURN CODE DATA:http_status_code TYPE i, status_text TYPE string. CALL METHOD http_client->response->get_status IMPORTING code = http_status_code reason = status_text . WRITE: / 'HTTP_STATUS_CODE = ', http_status_code, / 'STATUS_TEXT = ', status_text. "READ RESPONSE DATA DATA:w_result TYPE string. CALL METHOD http_client->response->get_cdata RECEIVING data = w_result . * 获取返回的数据 DATA: r_value TYPE string, r_value1 TYPE string, r_fields TYPE tihttpnvp, r_h_fields TYPE tihttpnvp. http_client->response->get_header_fields( CHANGING fields = r_h_fields ). "返回表数据
